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);
188 unsigned long flags = 0;
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 uport->cons->cflag = 0;
228 * Initialise the hardware port settings.
230 uart_change_speed(tty, state, NULL);
233 * Setup the RTS and DTR signals once the
234 * port is open and ready to respond.
236 if (init_hw && C_BAUD(tty))
237 uart_port_dtr_rts(uport, 1);
241 * This is to allow setserial on this port. People may want to set
242 * port/irq/type and then reconfigure the port properly if it failed
245 if (retval && capable(CAP_SYS_ADMIN))
251 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
254 struct tty_port *port = &state->port;
257 if (tty_port_initialized(port))
260 retval = uart_port_startup(tty, state, init_hw);
262 set_bit(TTY_IO_ERROR, &tty->flags);
268 * This routine will shutdown a serial port; interrupts are disabled, and
269 * DTR is dropped if the hangup on close termio flag is on. Calls to
270 * uart_shutdown are serialised by the per-port semaphore.
272 * uport == NULL if uart_port has already been removed
274 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
276 struct uart_port *uport = uart_port_check(state);
277 struct tty_port *port = &state->port;
278 unsigned long flags = 0;
279 char *xmit_buf = NULL;
282 * Set the TTY IO error marker
285 set_bit(TTY_IO_ERROR, &tty->flags);
287 if (tty_port_initialized(port)) {
288 tty_port_set_initialized(port, 0);
291 * Turn off DTR and RTS early.
293 if (uport && uart_console(uport) && tty)
294 uport->cons->cflag = tty->termios.c_cflag;
296 if (!tty || C_HUPCL(tty))
297 uart_port_dtr_rts(uport, 0);
299 uart_port_shutdown(port);
303 * It's possible for shutdown to be called after suspend if we get
304 * a DCD drop (hangup) at just the right time. Clear suspended bit so
305 * we don't try to resume a port that has been shutdown.
307 tty_port_set_suspended(port, 0);
310 * Do not free() the transmit buffer page under the port lock since
311 * this can create various circular locking scenarios. For instance,
312 * console driver may need to allocate/free a debug object, which
313 * can endup in printk() recursion.
315 uart_port_lock(state, flags);
316 xmit_buf = state->xmit.buf;
317 state->xmit.buf = NULL;
318 uart_port_unlock(uport, flags);
321 free_page((unsigned long)xmit_buf);
325 * uart_update_timeout - update per-port FIFO timeout.
326 * @port: uart_port structure describing the port
327 * @cflag: termios cflag value
328 * @baud: speed of the port
330 * Set the port FIFO timeout value. The @cflag value should
331 * reflect the actual hardware settings.
334 uart_update_timeout(struct uart_port *port, unsigned int cflag,
339 /* byte size and parity */
340 switch (cflag & CSIZE) {
361 * The total number of bits to be transmitted in the fifo.
363 bits = bits * port->fifosize;
366 * Figure the timeout to send the above number of bits.
367 * Add .02 seconds of slop
369 port->timeout = (HZ * bits) / baud + HZ/50;
372 EXPORT_SYMBOL(uart_update_timeout);
375 * uart_get_baud_rate - return baud rate for a particular port
376 * @port: uart_port structure describing the port in question.
377 * @termios: desired termios settings.
378 * @old: old termios (or NULL)
379 * @min: minimum acceptable baud rate
380 * @max: maximum acceptable baud rate
382 * Decode the termios structure into a numeric baud rate,
383 * taking account of the magic 38400 baud rate (with spd_*
384 * flags), and mapping the %B0 rate to 9600 baud.
386 * If the new baud rate is invalid, try the old termios setting.
387 * If it's still invalid, we try 9600 baud.
389 * Update the @termios structure to reflect the baud rate
390 * we're actually going to be using. Don't do this for the case
391 * where B0 is requested ("hang up").
394 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
395 struct ktermios *old, unsigned int min, unsigned int max)
399 unsigned int altbaud;
401 upf_t flags = port->flags & UPF_SPD_MASK;
421 for (try = 0; try < 2; try++) {
422 baud = tty_termios_baud_rate(termios);
425 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
428 if (try == 0 && baud == 38400)
432 * Special case: B0 rate.
439 if (baud >= min && baud <= max)
443 * Oops, the quotient was zero. Try again with
444 * the old baud rate if possible.
446 termios->c_cflag &= ~CBAUD;
448 baud = tty_termios_baud_rate(old);
450 tty_termios_encode_baud_rate(termios,
457 * As a last resort, if the range cannot be met then clip to
458 * the nearest chip supported rate.
462 tty_termios_encode_baud_rate(termios,
465 tty_termios_encode_baud_rate(termios,
469 /* Should never happen */
474 EXPORT_SYMBOL(uart_get_baud_rate);
477 * uart_get_divisor - return uart clock divisor
478 * @port: uart_port structure describing the port.
479 * @baud: desired baud rate
481 * Calculate the uart clock divisor for the port.
484 uart_get_divisor(struct uart_port *port, unsigned int baud)
489 * Old custom speed handling.
491 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
492 quot = port->custom_divisor;
494 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
499 EXPORT_SYMBOL(uart_get_divisor);
501 /* Caller holds port mutex */
502 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
503 struct ktermios *old_termios)
505 struct uart_port *uport = uart_port_check(state);
506 struct ktermios *termios;
510 * If we have no tty, termios, or the port does not exist,
511 * then we can't set the parameters for this port.
513 if (!tty || uport->type == PORT_UNKNOWN)
516 termios = &tty->termios;
517 uport->ops->set_termios(uport, termios, old_termios);
520 * Set modem status enables based on termios cflag
522 spin_lock_irq(&uport->lock);
523 if (termios->c_cflag & CRTSCTS)
524 uport->status |= UPSTAT_CTS_ENABLE;
526 uport->status &= ~UPSTAT_CTS_ENABLE;
528 if (termios->c_cflag & CLOCAL)
529 uport->status &= ~UPSTAT_DCD_ENABLE;
531 uport->status |= UPSTAT_DCD_ENABLE;
533 /* reset sw-assisted CTS flow control based on (possibly) new mode */
534 hw_stopped = uport->hw_stopped;
535 uport->hw_stopped = uart_softcts_mode(uport) &&
536 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
537 if (uport->hw_stopped) {
539 uport->ops->stop_tx(uport);
544 spin_unlock_irq(&uport->lock);
547 static int uart_put_char(struct tty_struct *tty, unsigned char c)
549 struct uart_state *state = tty->driver_data;
550 struct uart_port *port;
551 struct circ_buf *circ;
556 port = uart_port_lock(state, flags);
558 uart_port_unlock(port, flags);
562 if (port && uart_circ_chars_free(circ) != 0) {
563 circ->buf[circ->head] = c;
564 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
567 uart_port_unlock(port, flags);
571 static void uart_flush_chars(struct tty_struct *tty)
576 static int uart_write(struct tty_struct *tty,
577 const unsigned char *buf, int count)
579 struct uart_state *state = tty->driver_data;
580 struct uart_port *port;
581 struct circ_buf *circ;
586 * This means you called this function _after_ the port was
587 * closed. No cookie for you.
594 port = uart_port_lock(state, flags);
597 uart_port_unlock(port, flags);
602 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
607 memcpy(circ->buf + circ->head, buf, c);
608 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
615 uart_port_unlock(port, flags);
619 static int uart_write_room(struct tty_struct *tty)
621 struct uart_state *state = tty->driver_data;
622 struct uart_port *port;
626 port = uart_port_lock(state, flags);
627 ret = uart_circ_chars_free(&state->xmit);
628 uart_port_unlock(port, flags);
632 static int uart_chars_in_buffer(struct tty_struct *tty)
634 struct uart_state *state = tty->driver_data;
635 struct uart_port *port;
639 port = uart_port_lock(state, flags);
640 ret = uart_circ_chars_pending(&state->xmit);
641 uart_port_unlock(port, flags);
645 static void uart_flush_buffer(struct tty_struct *tty)
647 struct uart_state *state = tty->driver_data;
648 struct uart_port *port;
652 * This means you called this function _after_ the port was
653 * closed. No cookie for you.
660 pr_debug("uart_flush_buffer(%d) called\n", tty->index);
662 port = uart_port_lock(state, flags);
665 uart_circ_clear(&state->xmit);
666 if (port->ops->flush_buffer)
667 port->ops->flush_buffer(port);
668 uart_port_unlock(port, flags);
669 tty_port_tty_wakeup(&state->port);
673 * This function is used to send a high-priority XON/XOFF character to
676 static void uart_send_xchar(struct tty_struct *tty, char ch)
678 struct uart_state *state = tty->driver_data;
679 struct uart_port *port;
682 port = uart_port_ref(state);
686 if (port->ops->send_xchar)
687 port->ops->send_xchar(port, ch);
689 spin_lock_irqsave(&port->lock, flags);
692 port->ops->start_tx(port);
693 spin_unlock_irqrestore(&port->lock, flags);
695 uart_port_deref(port);
698 static void uart_throttle(struct tty_struct *tty)
700 struct uart_state *state = tty->driver_data;
701 upstat_t mask = UPSTAT_SYNC_FIFO;
702 struct uart_port *port;
704 port = uart_port_ref(state);
709 mask |= UPSTAT_AUTOXOFF;
711 mask |= UPSTAT_AUTORTS;
713 if (port->status & mask) {
714 port->ops->throttle(port);
715 mask &= ~port->status;
718 if (mask & UPSTAT_AUTORTS)
719 uart_clear_mctrl(port, TIOCM_RTS);
721 if (mask & UPSTAT_AUTOXOFF)
722 uart_send_xchar(tty, STOP_CHAR(tty));
724 uart_port_deref(port);
727 static void uart_unthrottle(struct tty_struct *tty)
729 struct uart_state *state = tty->driver_data;
730 upstat_t mask = UPSTAT_SYNC_FIFO;
731 struct uart_port *port;
733 port = uart_port_ref(state);
738 mask |= UPSTAT_AUTOXOFF;
740 mask |= UPSTAT_AUTORTS;
742 if (port->status & mask) {
743 port->ops->unthrottle(port);
744 mask &= ~port->status;
747 if (mask & UPSTAT_AUTORTS)
748 uart_set_mctrl(port, TIOCM_RTS);
750 if (mask & UPSTAT_AUTOXOFF)
751 uart_send_xchar(tty, START_CHAR(tty));
753 uart_port_deref(port);
756 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
758 struct uart_state *state = container_of(port, struct uart_state, port);
759 struct uart_port *uport;
763 * Ensure the state we copy is consistent and no hardware changes
766 mutex_lock(&port->mutex);
767 uport = uart_port_check(state);
771 retinfo->type = uport->type;
772 retinfo->line = uport->line;
773 retinfo->port = uport->iobase;
774 if (HIGH_BITS_OFFSET)
775 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
776 retinfo->irq = uport->irq;
777 retinfo->flags = (__force int)uport->flags;
778 retinfo->xmit_fifo_size = uport->fifosize;
779 retinfo->baud_base = uport->uartclk / 16;
780 retinfo->close_delay = jiffies_to_msecs(port->close_delay) / 10;
781 retinfo->closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
782 ASYNC_CLOSING_WAIT_NONE :
783 jiffies_to_msecs(port->closing_wait) / 10;
784 retinfo->custom_divisor = uport->custom_divisor;
785 retinfo->hub6 = uport->hub6;
786 retinfo->io_type = uport->iotype;
787 retinfo->iomem_reg_shift = uport->regshift;
788 retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
792 mutex_unlock(&port->mutex);
796 static int uart_get_info_user(struct tty_struct *tty,
797 struct serial_struct *ss)
799 struct uart_state *state = tty->driver_data;
800 struct tty_port *port = &state->port;
802 return uart_get_info(port, ss) < 0 ? -EIO : 0;
805 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
806 struct uart_state *state,
807 struct serial_struct *new_info)
809 struct uart_port *uport = uart_port_check(state);
810 unsigned long new_port;
811 unsigned int change_irq, change_port, closing_wait;
812 unsigned int old_custom_divisor, close_delay;
813 upf_t old_flags, new_flags;
819 new_port = new_info->port;
820 if (HIGH_BITS_OFFSET)
821 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
823 new_info->irq = irq_canonicalize(new_info->irq);
824 close_delay = msecs_to_jiffies(new_info->close_delay * 10);
825 closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
826 ASYNC_CLOSING_WAIT_NONE :
827 msecs_to_jiffies(new_info->closing_wait * 10);
830 change_irq = !(uport->flags & UPF_FIXED_PORT)
831 && new_info->irq != uport->irq;
834 * Since changing the 'type' of the port changes its resource
835 * allocations, we should treat type changes the same as
838 change_port = !(uport->flags & UPF_FIXED_PORT)
839 && (new_port != uport->iobase ||
840 (unsigned long)new_info->iomem_base != uport->mapbase ||
841 new_info->hub6 != uport->hub6 ||
842 new_info->io_type != uport->iotype ||
843 new_info->iomem_reg_shift != uport->regshift ||
844 new_info->type != uport->type);
846 old_flags = uport->flags;
847 new_flags = (__force upf_t)new_info->flags;
848 old_custom_divisor = uport->custom_divisor;
850 if (!capable(CAP_SYS_ADMIN)) {
852 if (change_irq || change_port ||
853 (new_info->baud_base != uport->uartclk / 16) ||
854 (close_delay != port->close_delay) ||
855 (closing_wait != port->closing_wait) ||
856 (new_info->xmit_fifo_size &&
857 new_info->xmit_fifo_size != uport->fifosize) ||
858 (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
860 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
861 (new_flags & UPF_USR_MASK));
862 uport->custom_divisor = new_info->custom_divisor;
866 retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
867 if (retval && (change_irq || change_port))
871 * Ask the low level driver to verify the settings.
873 if (uport->ops->verify_port)
874 retval = uport->ops->verify_port(uport, new_info);
876 if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
877 (new_info->baud_base < 9600))
883 if (change_port || change_irq) {
887 * Make sure that we are the sole user of this port.
889 if (tty_port_users(port) > 1)
893 * We need to shutdown the serial port at the old
894 * port/type/irq combination.
896 uart_shutdown(tty, state);
900 unsigned long old_iobase, old_mapbase;
901 unsigned int old_type, old_iotype, old_hub6, old_shift;
903 old_iobase = uport->iobase;
904 old_mapbase = uport->mapbase;
905 old_type = uport->type;
906 old_hub6 = uport->hub6;
907 old_iotype = uport->iotype;
908 old_shift = uport->regshift;
911 * Free and release old regions
913 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
914 uport->ops->release_port(uport);
916 uport->iobase = new_port;
917 uport->type = new_info->type;
918 uport->hub6 = new_info->hub6;
919 uport->iotype = new_info->io_type;
920 uport->regshift = new_info->iomem_reg_shift;
921 uport->mapbase = (unsigned long)new_info->iomem_base;
924 * Claim and map the new regions
926 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
927 retval = uport->ops->request_port(uport);
929 /* Always success - Jean II */
934 * If we fail to request resources for the
935 * new port, try to restore the old settings.
938 uport->iobase = old_iobase;
939 uport->type = old_type;
940 uport->hub6 = old_hub6;
941 uport->iotype = old_iotype;
942 uport->regshift = old_shift;
943 uport->mapbase = old_mapbase;
945 if (old_type != PORT_UNKNOWN) {
946 retval = uport->ops->request_port(uport);
948 * If we failed to restore the old settings,
952 uport->type = PORT_UNKNOWN;
960 /* Added to return the correct error -Ram Gupta */
966 uport->irq = new_info->irq;
967 if (!(uport->flags & UPF_FIXED_PORT))
968 uport->uartclk = new_info->baud_base * 16;
969 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
970 (new_flags & UPF_CHANGE_MASK);
971 uport->custom_divisor = new_info->custom_divisor;
972 port->close_delay = close_delay;
973 port->closing_wait = closing_wait;
974 if (new_info->xmit_fifo_size)
975 uport->fifosize = new_info->xmit_fifo_size;
979 if (uport->type == PORT_UNKNOWN)
981 if (tty_port_initialized(port)) {
982 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
983 old_custom_divisor != uport->custom_divisor) {
985 * If they're setting up a custom divisor or speed,
986 * instead of clearing it, then bitch about it.
988 if (uport->flags & UPF_SPD_MASK) {
989 dev_notice_ratelimited(uport->dev,
990 "%s sets custom speed on %s. This is deprecated.\n",
992 tty_name(port->tty));
994 uart_change_speed(tty, state, NULL);
997 retval = uart_startup(tty, state, 1);
999 tty_port_set_initialized(port, true);
1007 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1009 struct uart_state *state = tty->driver_data;
1010 struct tty_port *port = &state->port;
1013 down_write(&tty->termios_rwsem);
1015 * This semaphore protects port->count. It is also
1016 * very useful to prevent opens. Also, take the
1017 * port configuration semaphore to make sure that a
1018 * module insertion/removal doesn't change anything
1021 mutex_lock(&port->mutex);
1022 retval = uart_set_info(tty, port, state, ss);
1023 mutex_unlock(&port->mutex);
1024 up_write(&tty->termios_rwsem);
1029 * uart_get_lsr_info - get line status register info
1030 * @tty: tty associated with the UART
1031 * @state: UART being queried
1032 * @value: returned modem value
1034 static int uart_get_lsr_info(struct tty_struct *tty,
1035 struct uart_state *state, unsigned int __user *value)
1037 struct uart_port *uport = uart_port_check(state);
1038 unsigned int result;
1040 result = uport->ops->tx_empty(uport);
1043 * If we're about to load something into the transmit
1044 * register, we'll pretend the transmitter isn't empty to
1045 * avoid a race condition (depending on when the transmit
1046 * interrupt happens).
1048 if (uport->x_char ||
1049 ((uart_circ_chars_pending(&state->xmit) > 0) &&
1050 !uart_tx_stopped(uport)))
1051 result &= ~TIOCSER_TEMT;
1053 return put_user(result, value);
1056 static int uart_tiocmget(struct tty_struct *tty)
1058 struct uart_state *state = tty->driver_data;
1059 struct tty_port *port = &state->port;
1060 struct uart_port *uport;
1063 mutex_lock(&port->mutex);
1064 uport = uart_port_check(state);
1068 if (!tty_io_error(tty)) {
1069 result = uport->mctrl;
1070 spin_lock_irq(&uport->lock);
1071 result |= uport->ops->get_mctrl(uport);
1072 spin_unlock_irq(&uport->lock);
1075 mutex_unlock(&port->mutex);
1080 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1082 struct uart_state *state = tty->driver_data;
1083 struct tty_port *port = &state->port;
1084 struct uart_port *uport;
1087 mutex_lock(&port->mutex);
1088 uport = uart_port_check(state);
1092 if (!tty_io_error(tty)) {
1093 uart_update_mctrl(uport, set, clear);
1097 mutex_unlock(&port->mutex);
1101 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1103 struct uart_state *state = tty->driver_data;
1104 struct tty_port *port = &state->port;
1105 struct uart_port *uport;
1108 mutex_lock(&port->mutex);
1109 uport = uart_port_check(state);
1113 if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1114 uport->ops->break_ctl(uport, break_state);
1117 mutex_unlock(&port->mutex);
1121 static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1123 struct tty_port *port = &state->port;
1124 struct uart_port *uport;
1127 if (!capable(CAP_SYS_ADMIN))
1131 * Take the per-port semaphore. This prevents count from
1132 * changing, and hence any extra opens of the port while
1133 * we're auto-configuring.
1135 if (mutex_lock_interruptible(&port->mutex))
1136 return -ERESTARTSYS;
1138 uport = uart_port_check(state);
1145 if (tty_port_users(port) == 1) {
1146 uart_shutdown(tty, state);
1149 * If we already have a port type configured,
1150 * we must release its resources.
1152 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1153 uport->ops->release_port(uport);
1155 flags = UART_CONFIG_TYPE;
1156 if (uport->flags & UPF_AUTO_IRQ)
1157 flags |= UART_CONFIG_IRQ;
1160 * This will claim the ports resources if
1163 uport->ops->config_port(uport, flags);
1165 ret = uart_startup(tty, state, 1);
1167 tty_port_set_initialized(port, true);
1172 mutex_unlock(&port->mutex);
1176 static void uart_enable_ms(struct uart_port *uport)
1179 * Force modem status interrupts on
1181 if (uport->ops->enable_ms)
1182 uport->ops->enable_ms(uport);
1186 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1187 * - mask passed in arg for lines of interest
1188 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1189 * Caller should use TIOCGICOUNT to see which one it was
1191 * FIXME: This wants extracting into a common all driver implementation
1192 * of TIOCMWAIT using tty_port.
1194 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1196 struct uart_port *uport;
1197 struct tty_port *port = &state->port;
1198 DECLARE_WAITQUEUE(wait, current);
1199 struct uart_icount cprev, cnow;
1203 * note the counters on entry
1205 uport = uart_port_ref(state);
1208 spin_lock_irq(&uport->lock);
1209 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1210 uart_enable_ms(uport);
1211 spin_unlock_irq(&uport->lock);
1213 add_wait_queue(&port->delta_msr_wait, &wait);
1215 spin_lock_irq(&uport->lock);
1216 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1217 spin_unlock_irq(&uport->lock);
1219 set_current_state(TASK_INTERRUPTIBLE);
1221 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1222 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1223 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1224 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1231 /* see if a signal did it */
1232 if (signal_pending(current)) {
1239 __set_current_state(TASK_RUNNING);
1240 remove_wait_queue(&port->delta_msr_wait, &wait);
1241 uart_port_deref(uport);
1247 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1248 * Return: write counters to the user passed counter struct
1249 * NB: both 1->0 and 0->1 transitions are counted except for
1250 * RI where only 0->1 is counted.
1252 static int uart_get_icount(struct tty_struct *tty,
1253 struct serial_icounter_struct *icount)
1255 struct uart_state *state = tty->driver_data;
1256 struct uart_icount cnow;
1257 struct uart_port *uport;
1259 uport = uart_port_ref(state);
1262 spin_lock_irq(&uport->lock);
1263 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1264 spin_unlock_irq(&uport->lock);
1265 uart_port_deref(uport);
1267 icount->cts = cnow.cts;
1268 icount->dsr = cnow.dsr;
1269 icount->rng = cnow.rng;
1270 icount->dcd = cnow.dcd;
1271 icount->rx = cnow.rx;
1272 icount->tx = cnow.tx;
1273 icount->frame = cnow.frame;
1274 icount->overrun = cnow.overrun;
1275 icount->parity = cnow.parity;
1276 icount->brk = cnow.brk;
1277 icount->buf_overrun = cnow.buf_overrun;
1282 static int uart_get_rs485_config(struct uart_port *port,
1283 struct serial_rs485 __user *rs485)
1285 unsigned long flags;
1286 struct serial_rs485 aux;
1288 spin_lock_irqsave(&port->lock, flags);
1290 spin_unlock_irqrestore(&port->lock, flags);
1292 if (copy_to_user(rs485, &aux, sizeof(aux)))
1298 static int uart_set_rs485_config(struct uart_port *port,
1299 struct serial_rs485 __user *rs485_user)
1301 struct serial_rs485 rs485;
1303 unsigned long flags;
1305 if (!port->rs485_config)
1308 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1311 spin_lock_irqsave(&port->lock, flags);
1312 ret = port->rs485_config(port, &rs485);
1313 spin_unlock_irqrestore(&port->lock, flags);
1317 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1323 static int uart_get_iso7816_config(struct uart_port *port,
1324 struct serial_iso7816 __user *iso7816)
1326 unsigned long flags;
1327 struct serial_iso7816 aux;
1329 if (!port->iso7816_config)
1332 spin_lock_irqsave(&port->lock, flags);
1333 aux = port->iso7816;
1334 spin_unlock_irqrestore(&port->lock, flags);
1336 if (copy_to_user(iso7816, &aux, sizeof(aux)))
1342 static int uart_set_iso7816_config(struct uart_port *port,
1343 struct serial_iso7816 __user *iso7816_user)
1345 struct serial_iso7816 iso7816;
1347 unsigned long flags;
1349 if (!port->iso7816_config)
1352 if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1356 * There are 5 words reserved for future use. Check that userspace
1357 * doesn't put stuff in there to prevent breakages in the future.
1359 for (i = 0; i < 5; i++)
1360 if (iso7816.reserved[i])
1363 spin_lock_irqsave(&port->lock, flags);
1364 ret = port->iso7816_config(port, &iso7816);
1365 spin_unlock_irqrestore(&port->lock, flags);
1369 if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1376 * Called via sys_ioctl. We can use spin_lock_irq() here.
1379 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1381 struct uart_state *state = tty->driver_data;
1382 struct tty_port *port = &state->port;
1383 struct uart_port *uport;
1384 void __user *uarg = (void __user *)arg;
1385 int ret = -ENOIOCTLCMD;
1389 * These ioctls don't rely on the hardware to be present.
1393 down_write(&tty->termios_rwsem);
1394 ret = uart_do_autoconfig(tty, state);
1395 up_write(&tty->termios_rwsem);
1399 if (ret != -ENOIOCTLCMD)
1402 if (tty_io_error(tty)) {
1408 * The following should only be used when hardware is present.
1412 ret = uart_wait_modem_status(state, arg);
1416 if (ret != -ENOIOCTLCMD)
1419 mutex_lock(&port->mutex);
1420 uport = uart_port_check(state);
1422 if (!uport || tty_io_error(tty)) {
1428 * All these rely on hardware being present and need to be
1429 * protected against the tty being hung up.
1433 case TIOCSERGETLSR: /* Get line status register */
1434 ret = uart_get_lsr_info(tty, state, uarg);
1438 ret = uart_get_rs485_config(uport, uarg);
1442 ret = uart_set_rs485_config(uport, uarg);
1446 ret = uart_set_iso7816_config(state->uart_port, uarg);
1450 ret = uart_get_iso7816_config(state->uart_port, uarg);
1453 if (uport->ops->ioctl)
1454 ret = uport->ops->ioctl(uport, cmd, arg);
1458 mutex_unlock(&port->mutex);
1463 static void uart_set_ldisc(struct tty_struct *tty)
1465 struct uart_state *state = tty->driver_data;
1466 struct uart_port *uport;
1467 struct tty_port *port = &state->port;
1469 if (!tty_port_initialized(port))
1472 mutex_lock(&state->port.mutex);
1473 uport = uart_port_check(state);
1474 if (uport && uport->ops->set_ldisc)
1475 uport->ops->set_ldisc(uport, &tty->termios);
1476 mutex_unlock(&state->port.mutex);
1479 static void uart_set_termios(struct tty_struct *tty,
1480 struct ktermios *old_termios)
1482 struct uart_state *state = tty->driver_data;
1483 struct uart_port *uport;
1484 unsigned int cflag = tty->termios.c_cflag;
1485 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1486 bool sw_changed = false;
1488 mutex_lock(&state->port.mutex);
1489 uport = uart_port_check(state);
1494 * Drivers doing software flow control also need to know
1495 * about changes to these input settings.
1497 if (uport->flags & UPF_SOFT_FLOW) {
1498 iflag_mask |= IXANY|IXON|IXOFF;
1500 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1501 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1505 * These are the bits that are used to setup various
1506 * flags in the low level driver. We can ignore the Bfoo
1507 * bits in c_cflag; c_[io]speed will always be set
1508 * appropriately by set_termios() in tty_ioctl.c
1510 if ((cflag ^ old_termios->c_cflag) == 0 &&
1511 tty->termios.c_ospeed == old_termios->c_ospeed &&
1512 tty->termios.c_ispeed == old_termios->c_ispeed &&
1513 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1518 uart_change_speed(tty, state, old_termios);
1519 /* reload cflag from termios; port driver may have overridden flags */
1520 cflag = tty->termios.c_cflag;
1522 /* Handle transition to B0 status */
1523 if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1524 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1525 /* Handle transition away from B0 status */
1526 else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1527 unsigned int mask = TIOCM_DTR;
1529 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1531 uart_set_mctrl(uport, mask);
1534 mutex_unlock(&state->port.mutex);
1538 * Calls to uart_close() are serialised via the tty_lock in
1539 * drivers/tty/tty_io.c:tty_release()
1540 * drivers/tty/tty_io.c:do_tty_hangup()
1542 static void uart_close(struct tty_struct *tty, struct file *filp)
1544 struct uart_state *state = tty->driver_data;
1547 struct uart_driver *drv = tty->driver->driver_state;
1548 struct tty_port *port;
1550 state = drv->state + tty->index;
1551 port = &state->port;
1552 spin_lock_irq(&port->lock);
1554 spin_unlock_irq(&port->lock);
1558 pr_debug("uart_close(%d) called\n", tty->index);
1560 tty_port_close(tty->port, tty, filp);
1563 static void uart_tty_port_shutdown(struct tty_port *port)
1565 struct uart_state *state = container_of(port, struct uart_state, port);
1566 struct uart_port *uport = uart_port_check(state);
1569 * At this point, we stop accepting input. To do this, we
1570 * disable the receive line status interrupts.
1572 if (WARN(!uport, "detached port still initialized!\n"))
1575 spin_lock_irq(&uport->lock);
1576 uport->ops->stop_rx(uport);
1577 spin_unlock_irq(&uport->lock);
1579 uart_port_shutdown(port);
1582 * It's possible for shutdown to be called after suspend if we get
1583 * a DCD drop (hangup) at just the right time. Clear suspended bit so
1584 * we don't try to resume a port that has been shutdown.
1586 tty_port_set_suspended(port, 0);
1588 uart_change_pm(state, UART_PM_STATE_OFF);
1592 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1594 struct uart_state *state = tty->driver_data;
1595 struct uart_port *port;
1596 unsigned long char_time, expire;
1598 port = uart_port_ref(state);
1602 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1603 uart_port_deref(port);
1608 * Set the check interval to be 1/5 of the estimated time to
1609 * send a single character, and make it at least 1. The check
1610 * interval should also be less than the timeout.
1612 * Note: we have to use pretty tight timings here to satisfy
1615 char_time = (port->timeout - HZ/50) / port->fifosize;
1616 char_time = char_time / 5;
1619 if (timeout && timeout < char_time)
1620 char_time = timeout;
1623 * If the transmitter hasn't cleared in twice the approximate
1624 * amount of time to send the entire FIFO, it probably won't
1625 * ever clear. This assumes the UART isn't doing flow
1626 * control, which is currently the case. Hence, if it ever
1627 * takes longer than port->timeout, this is probably due to a
1628 * UART bug of some kind. So, we clamp the timeout parameter at
1631 if (timeout == 0 || timeout > 2 * port->timeout)
1632 timeout = 2 * port->timeout;
1634 expire = jiffies + timeout;
1636 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1637 port->line, jiffies, expire);
1640 * Check whether the transmitter is empty every 'char_time'.
1641 * 'timeout' / 'expire' give us the maximum amount of time
1644 while (!port->ops->tx_empty(port)) {
1645 msleep_interruptible(jiffies_to_msecs(char_time));
1646 if (signal_pending(current))
1648 if (time_after(jiffies, expire))
1651 uart_port_deref(port);
1655 * Calls to uart_hangup() are serialised by the tty_lock in
1656 * drivers/tty/tty_io.c:do_tty_hangup()
1657 * This runs from a workqueue and can sleep for a _short_ time only.
1659 static void uart_hangup(struct tty_struct *tty)
1661 struct uart_state *state = tty->driver_data;
1662 struct tty_port *port = &state->port;
1663 struct uart_port *uport;
1664 unsigned long flags;
1666 pr_debug("uart_hangup(%d)\n", tty->index);
1668 mutex_lock(&port->mutex);
1669 uport = uart_port_check(state);
1670 WARN(!uport, "hangup of detached port!\n");
1672 if (tty_port_active(port)) {
1673 uart_flush_buffer(tty);
1674 uart_shutdown(tty, state);
1675 spin_lock_irqsave(&port->lock, flags);
1677 spin_unlock_irqrestore(&port->lock, flags);
1678 tty_port_set_active(port, 0);
1679 tty_port_tty_set(port, NULL);
1680 if (uport && !uart_console(uport))
1681 uart_change_pm(state, UART_PM_STATE_OFF);
1682 wake_up_interruptible(&port->open_wait);
1683 wake_up_interruptible(&port->delta_msr_wait);
1685 mutex_unlock(&port->mutex);
1688 /* uport == NULL if uart_port has already been removed */
1689 static void uart_port_shutdown(struct tty_port *port)
1691 struct uart_state *state = container_of(port, struct uart_state, port);
1692 struct uart_port *uport = uart_port_check(state);
1695 * clear delta_msr_wait queue to avoid mem leaks: we may free
1696 * the irq here so the queue might never be woken up. Note
1697 * that we won't end up waiting on delta_msr_wait again since
1698 * any outstanding file descriptors should be pointing at
1699 * hung_up_tty_fops now.
1701 wake_up_interruptible(&port->delta_msr_wait);
1704 * Free the IRQ and disable the port.
1707 uport->ops->shutdown(uport);
1710 * Ensure that the IRQ handler isn't running on another CPU.
1713 synchronize_irq(uport->irq);
1716 static int uart_carrier_raised(struct tty_port *port)
1718 struct uart_state *state = container_of(port, struct uart_state, port);
1719 struct uart_port *uport;
1722 uport = uart_port_ref(state);
1724 * Should never observe uport == NULL since checks for hangup should
1725 * abort the tty_port_block_til_ready() loop before checking for carrier
1726 * raised -- but report carrier raised if it does anyway so open will
1727 * continue and not sleep
1729 if (WARN_ON(!uport))
1731 spin_lock_irq(&uport->lock);
1732 uart_enable_ms(uport);
1733 mctrl = uport->ops->get_mctrl(uport);
1734 spin_unlock_irq(&uport->lock);
1735 uart_port_deref(uport);
1736 if (mctrl & TIOCM_CAR)
1741 static void uart_dtr_rts(struct tty_port *port, int raise)
1743 struct uart_state *state = container_of(port, struct uart_state, port);
1744 struct uart_port *uport;
1746 uport = uart_port_ref(state);
1749 uart_port_dtr_rts(uport, raise);
1750 uart_port_deref(uport);
1753 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1755 struct uart_driver *drv = driver->driver_state;
1756 struct uart_state *state = drv->state + tty->index;
1758 tty->driver_data = state;
1760 return tty_standard_install(driver, tty);
1764 * Calls to uart_open are serialised by the tty_lock in
1765 * drivers/tty/tty_io.c:tty_open()
1766 * Note that if this fails, then uart_close() _will_ be called.
1768 * In time, we want to scrap the "opening nonpresent ports"
1769 * behaviour and implement an alternative way for setserial
1770 * to set base addresses/ports/types. This will allow us to
1771 * get rid of a certain amount of extra tests.
1773 static int uart_open(struct tty_struct *tty, struct file *filp)
1775 struct uart_state *state = tty->driver_data;
1778 retval = tty_port_open(&state->port, tty, filp);
1785 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1787 struct uart_state *state = container_of(port, struct uart_state, port);
1788 struct uart_port *uport;
1791 uport = uart_port_check(state);
1792 if (!uport || uport->flags & UPF_DEAD)
1796 * Start up the serial port.
1798 ret = uart_startup(tty, state, 0);
1800 tty_port_set_active(port, 1);
1805 static const char *uart_type(struct uart_port *port)
1807 const char *str = NULL;
1809 if (port->ops->type)
1810 str = port->ops->type(port);
1818 #ifdef CONFIG_PROC_FS
1820 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1822 struct uart_state *state = drv->state + i;
1823 struct tty_port *port = &state->port;
1824 enum uart_pm_state pm_state;
1825 struct uart_port *uport;
1827 unsigned int status;
1830 mutex_lock(&port->mutex);
1831 uport = uart_port_check(state);
1835 mmio = uport->iotype >= UPIO_MEM;
1836 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
1837 uport->line, uart_type(uport),
1838 mmio ? "mmio:0x" : "port:",
1839 mmio ? (unsigned long long)uport->mapbase
1840 : (unsigned long long)uport->iobase,
1843 if (uport->type == PORT_UNKNOWN) {
1848 if (capable(CAP_SYS_ADMIN)) {
1849 pm_state = state->pm_state;
1850 if (pm_state != UART_PM_STATE_ON)
1851 uart_change_pm(state, UART_PM_STATE_ON);
1852 spin_lock_irq(&uport->lock);
1853 status = uport->ops->get_mctrl(uport);
1854 spin_unlock_irq(&uport->lock);
1855 if (pm_state != UART_PM_STATE_ON)
1856 uart_change_pm(state, pm_state);
1858 seq_printf(m, " tx:%d rx:%d",
1859 uport->icount.tx, uport->icount.rx);
1860 if (uport->icount.frame)
1861 seq_printf(m, " fe:%d", uport->icount.frame);
1862 if (uport->icount.parity)
1863 seq_printf(m, " pe:%d", uport->icount.parity);
1864 if (uport->icount.brk)
1865 seq_printf(m, " brk:%d", uport->icount.brk);
1866 if (uport->icount.overrun)
1867 seq_printf(m, " oe:%d", uport->icount.overrun);
1868 if (uport->icount.buf_overrun)
1869 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
1871 #define INFOBIT(bit, str) \
1872 if (uport->mctrl & (bit)) \
1873 strncat(stat_buf, (str), sizeof(stat_buf) - \
1874 strlen(stat_buf) - 2)
1875 #define STATBIT(bit, str) \
1876 if (status & (bit)) \
1877 strncat(stat_buf, (str), sizeof(stat_buf) - \
1878 strlen(stat_buf) - 2)
1882 INFOBIT(TIOCM_RTS, "|RTS");
1883 STATBIT(TIOCM_CTS, "|CTS");
1884 INFOBIT(TIOCM_DTR, "|DTR");
1885 STATBIT(TIOCM_DSR, "|DSR");
1886 STATBIT(TIOCM_CAR, "|CD");
1887 STATBIT(TIOCM_RNG, "|RI");
1891 seq_puts(m, stat_buf);
1897 mutex_unlock(&port->mutex);
1900 static int uart_proc_show(struct seq_file *m, void *v)
1902 struct tty_driver *ttydrv = m->private;
1903 struct uart_driver *drv = ttydrv->driver_state;
1906 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
1907 for (i = 0; i < drv->nr; i++)
1908 uart_line_info(m, drv, i);
1913 static inline bool uart_console_enabled(struct uart_port *port)
1915 return uart_console(port) && (port->cons->flags & CON_ENABLED);
1918 static void uart_port_spin_lock_init(struct uart_port *port)
1920 spin_lock_init(&port->lock);
1921 lockdep_set_class(&port->lock, &port_lock_key);
1924 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
1926 * uart_console_write - write a console message to a serial port
1927 * @port: the port to write the message
1928 * @s: array of characters
1929 * @count: number of characters in string to write
1930 * @putchar: function to write character to port
1932 void uart_console_write(struct uart_port *port, const char *s,
1934 void (*putchar)(struct uart_port *, int))
1938 for (i = 0; i < count; i++, s++) {
1940 putchar(port, '\r');
1944 EXPORT_SYMBOL_GPL(uart_console_write);
1947 * Check whether an invalid uart number has been specified, and
1948 * if so, search for the first available port that does have
1951 struct uart_port * __init
1952 uart_get_console(struct uart_port *ports, int nr, struct console *co)
1954 int idx = co->index;
1956 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1957 ports[idx].membase == NULL))
1958 for (idx = 0; idx < nr; idx++)
1959 if (ports[idx].iobase != 0 ||
1960 ports[idx].membase != NULL)
1969 * uart_parse_earlycon - Parse earlycon options
1970 * @p: ptr to 2nd field (ie., just beyond '<name>,')
1971 * @iotype: ptr for decoded iotype (out)
1972 * @addr: ptr for decoded mapbase/iobase (out)
1973 * @options: ptr for <options> field; NULL if not present (out)
1975 * Decodes earlycon kernel command line parameters of the form
1976 * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1977 * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1981 * earlycon=<name>,0x<addr>,<options>
1982 * console=<name>,0x<addr>,<options>
1984 * is also accepted; the returned @iotype will be UPIO_MEM.
1986 * Returns 0 on success or -EINVAL on failure
1988 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
1991 if (strncmp(p, "mmio,", 5) == 0) {
1994 } else if (strncmp(p, "mmio16,", 7) == 0) {
1995 *iotype = UPIO_MEM16;
1997 } else if (strncmp(p, "mmio32,", 7) == 0) {
1998 *iotype = UPIO_MEM32;
2000 } else if (strncmp(p, "mmio32be,", 9) == 0) {
2001 *iotype = UPIO_MEM32BE;
2003 } else if (strncmp(p, "mmio32native,", 13) == 0) {
2004 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2005 UPIO_MEM32BE : UPIO_MEM32;
2007 } else if (strncmp(p, "io,", 3) == 0) {
2008 *iotype = UPIO_PORT;
2010 } else if (strncmp(p, "0x", 2) == 0) {
2017 * Before you replace it with kstrtoull(), think about options separator
2018 * (',') it will not tolerate
2020 *addr = simple_strtoull(p, NULL, 0);
2028 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2031 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2032 * @options: pointer to option string
2033 * @baud: pointer to an 'int' variable for the baud rate.
2034 * @parity: pointer to an 'int' variable for the parity.
2035 * @bits: pointer to an 'int' variable for the number of data bits.
2036 * @flow: pointer to an 'int' variable for the flow control character.
2038 * uart_parse_options decodes a string containing the serial console
2039 * options. The format of the string is <baud><parity><bits><flow>,
2043 uart_parse_options(const char *options, int *baud, int *parity,
2044 int *bits, int *flow)
2046 const char *s = options;
2048 *baud = simple_strtoul(s, NULL, 10);
2049 while (*s >= '0' && *s <= '9')
2058 EXPORT_SYMBOL_GPL(uart_parse_options);
2061 * uart_set_options - setup the serial console parameters
2062 * @port: pointer to the serial ports uart_port structure
2063 * @co: console pointer
2065 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2066 * @bits: number of data bits
2067 * @flow: flow control character - 'r' (rts)
2070 uart_set_options(struct uart_port *port, struct console *co,
2071 int baud, int parity, int bits, int flow)
2073 struct ktermios termios;
2074 static struct ktermios dummy;
2077 * Ensure that the serial-console lock is initialised early.
2079 * Note that the console-enabled check is needed because of kgdboc,
2080 * which can end up calling uart_set_options() for an already enabled
2081 * console via tty_find_polling_driver() and uart_poll_init().
2083 if (!uart_console_enabled(port) && !port->console_reinit)
2084 uart_port_spin_lock_init(port);
2086 memset(&termios, 0, sizeof(struct ktermios));
2088 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2089 tty_termios_encode_baud_rate(&termios, baud, baud);
2092 termios.c_cflag |= CS7;
2094 termios.c_cflag |= CS8;
2098 termios.c_cflag |= PARODD;
2101 termios.c_cflag |= PARENB;
2106 termios.c_cflag |= CRTSCTS;
2109 * some uarts on other side don't support no flow control.
2110 * So we set * DTR in host uart to make them happy
2112 port->mctrl |= TIOCM_DTR;
2114 port->ops->set_termios(port, &termios, &dummy);
2116 * Allow the setting of the UART parameters with a NULL console
2120 co->cflag = termios.c_cflag;
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;
2256 * If that's unset, use the tty termios setting.
2258 if (port->tty && termios.c_cflag == 0)
2259 termios = port->tty->termios;
2261 if (console_suspend_enabled)
2262 uart_change_pm(state, UART_PM_STATE_ON);
2263 uport->ops->set_termios(uport, &termios, NULL);
2264 if (console_suspend_enabled)
2265 console_start(uport->cons);
2268 if (tty_port_suspended(port)) {
2269 const struct uart_ops *ops = uport->ops;
2272 uart_change_pm(state, UART_PM_STATE_ON);
2273 spin_lock_irq(&uport->lock);
2274 ops->set_mctrl(uport, 0);
2275 spin_unlock_irq(&uport->lock);
2276 if (console_suspend_enabled || !uart_console(uport)) {
2277 /* Protected by port mutex for now */
2278 struct tty_struct *tty = port->tty;
2280 ret = ops->startup(uport);
2283 uart_change_speed(tty, state, NULL);
2284 spin_lock_irq(&uport->lock);
2285 ops->set_mctrl(uport, uport->mctrl);
2286 ops->start_tx(uport);
2287 spin_unlock_irq(&uport->lock);
2288 tty_port_set_initialized(port, 1);
2291 * Failed to resume - maybe hardware went away?
2292 * Clear the "initialized" flag so we won't try
2293 * to call the low level drivers shutdown method.
2295 uart_shutdown(tty, state);
2299 tty_port_set_suspended(port, 0);
2302 mutex_unlock(&port->mutex);
2308 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2312 switch (port->iotype) {
2314 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2317 snprintf(address, sizeof(address),
2318 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2326 snprintf(address, sizeof(address),
2327 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2330 strlcpy(address, "*unknown*", sizeof(address));
2334 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2335 port->dev ? dev_name(port->dev) : "",
2336 port->dev ? ": " : "",
2338 address, port->irq, port->uartclk / 16, uart_type(port));
2342 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2343 struct uart_port *port)
2348 * If there isn't a port here, don't do anything further.
2350 if (!port->iobase && !port->mapbase && !port->membase)
2354 * Now do the auto configuration stuff. Note that config_port
2355 * is expected to claim the resources and map the port for us.
2358 if (port->flags & UPF_AUTO_IRQ)
2359 flags |= UART_CONFIG_IRQ;
2360 if (port->flags & UPF_BOOT_AUTOCONF) {
2361 if (!(port->flags & UPF_FIXED_TYPE)) {
2362 port->type = PORT_UNKNOWN;
2363 flags |= UART_CONFIG_TYPE;
2365 port->ops->config_port(port, flags);
2368 if (port->type != PORT_UNKNOWN) {
2369 unsigned long flags;
2371 uart_report_port(drv, port);
2373 /* Power up port for set_mctrl() */
2374 uart_change_pm(state, UART_PM_STATE_ON);
2377 * Ensure that the modem control lines are de-activated.
2378 * keep the DTR setting that is set in uart_set_options()
2379 * We probably don't need a spinlock around this, but
2381 spin_lock_irqsave(&port->lock, flags);
2382 port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
2383 spin_unlock_irqrestore(&port->lock, flags);
2386 * If this driver supports console, and it hasn't been
2387 * successfully registered yet, try to re-register it.
2388 * It may be that the port was not available.
2390 if (port->cons && !(port->cons->flags & CON_ENABLED))
2391 register_console(port->cons);
2394 * Power down all ports by default, except the
2395 * console if we have one.
2397 if (!uart_console(port))
2398 uart_change_pm(state, UART_PM_STATE_OFF);
2402 #ifdef CONFIG_CONSOLE_POLL
2404 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2406 struct uart_driver *drv = driver->driver_state;
2407 struct uart_state *state = drv->state + line;
2408 struct tty_port *tport;
2409 struct uart_port *port;
2416 tport = &state->port;
2417 mutex_lock(&tport->mutex);
2419 port = uart_port_check(state);
2420 if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2425 if (port->ops->poll_init) {
2427 * We don't set initialized as we only initialized the hw,
2428 * e.g. state->xmit is still uninitialized.
2430 if (!tty_port_initialized(tport))
2431 ret = port->ops->poll_init(port);
2434 if (!ret && options) {
2435 uart_parse_options(options, &baud, &parity, &bits, &flow);
2436 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2439 mutex_unlock(&tport->mutex);
2443 static int uart_poll_get_char(struct tty_driver *driver, int line)
2445 struct uart_driver *drv = driver->driver_state;
2446 struct uart_state *state = drv->state + line;
2447 struct uart_port *port;
2450 port = uart_port_ref(state);
2452 ret = port->ops->poll_get_char(port);
2453 uart_port_deref(port);
2459 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2461 struct uart_driver *drv = driver->driver_state;
2462 struct uart_state *state = drv->state + line;
2463 struct uart_port *port;
2465 port = uart_port_ref(state);
2470 port->ops->poll_put_char(port, '\r');
2471 port->ops->poll_put_char(port, ch);
2472 uart_port_deref(port);
2476 static const struct tty_operations uart_ops = {
2477 .install = uart_install,
2479 .close = uart_close,
2480 .write = uart_write,
2481 .put_char = uart_put_char,
2482 .flush_chars = uart_flush_chars,
2483 .write_room = uart_write_room,
2484 .chars_in_buffer= uart_chars_in_buffer,
2485 .flush_buffer = uart_flush_buffer,
2486 .ioctl = uart_ioctl,
2487 .throttle = uart_throttle,
2488 .unthrottle = uart_unthrottle,
2489 .send_xchar = uart_send_xchar,
2490 .set_termios = uart_set_termios,
2491 .set_ldisc = uart_set_ldisc,
2493 .start = uart_start,
2494 .hangup = uart_hangup,
2495 .break_ctl = uart_break_ctl,
2496 .wait_until_sent= uart_wait_until_sent,
2497 #ifdef CONFIG_PROC_FS
2498 .proc_show = uart_proc_show,
2500 .tiocmget = uart_tiocmget,
2501 .tiocmset = uart_tiocmset,
2502 .set_serial = uart_set_info_user,
2503 .get_serial = uart_get_info_user,
2504 .get_icount = uart_get_icount,
2505 #ifdef CONFIG_CONSOLE_POLL
2506 .poll_init = uart_poll_init,
2507 .poll_get_char = uart_poll_get_char,
2508 .poll_put_char = uart_poll_put_char,
2512 static const struct tty_port_operations uart_port_ops = {
2513 .carrier_raised = uart_carrier_raised,
2514 .dtr_rts = uart_dtr_rts,
2515 .activate = uart_port_activate,
2516 .shutdown = uart_tty_port_shutdown,
2520 * uart_register_driver - register a driver with the uart core layer
2521 * @drv: low level driver structure
2523 * Register a uart driver with the core driver. We in turn register
2524 * with the tty layer, and initialise the core driver per-port state.
2526 * We have a proc file in /proc/tty/driver which is named after the
2529 * drv->port should be NULL, and the per-port structures should be
2530 * registered using uart_add_one_port after this call has succeeded.
2532 int uart_register_driver(struct uart_driver *drv)
2534 struct tty_driver *normal;
2535 int i, retval = -ENOMEM;
2540 * Maybe we should be using a slab cache for this, especially if
2541 * we have a large number of ports to handle.
2543 drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2547 normal = alloc_tty_driver(drv->nr);
2551 drv->tty_driver = normal;
2553 normal->driver_name = drv->driver_name;
2554 normal->name = drv->dev_name;
2555 normal->major = drv->major;
2556 normal->minor_start = drv->minor;
2557 normal->type = TTY_DRIVER_TYPE_SERIAL;
2558 normal->subtype = SERIAL_TYPE_NORMAL;
2559 normal->init_termios = tty_std_termios;
2560 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2561 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2562 normal->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
2563 normal->driver_state = drv;
2564 tty_set_operations(normal, &uart_ops);
2567 * Initialise the UART state(s).
2569 for (i = 0; i < drv->nr; i++) {
2570 struct uart_state *state = drv->state + i;
2571 struct tty_port *port = &state->port;
2573 tty_port_init(port);
2574 port->ops = &uart_port_ops;
2577 retval = tty_register_driver(normal);
2581 for (i = 0; i < drv->nr; i++)
2582 tty_port_destroy(&drv->state[i].port);
2583 put_tty_driver(normal);
2591 * uart_unregister_driver - remove a driver from the uart core layer
2592 * @drv: low level driver structure
2594 * Remove all references to a driver from the core driver. The low
2595 * level driver must have removed all its ports via the
2596 * uart_remove_one_port() if it registered them with uart_add_one_port().
2597 * (ie, drv->port == NULL)
2599 void uart_unregister_driver(struct uart_driver *drv)
2601 struct tty_driver *p = drv->tty_driver;
2604 tty_unregister_driver(p);
2606 for (i = 0; i < drv->nr; i++)
2607 tty_port_destroy(&drv->state[i].port);
2610 drv->tty_driver = NULL;
2613 struct tty_driver *uart_console_device(struct console *co, int *index)
2615 struct uart_driver *p = co->data;
2617 return p->tty_driver;
2619 EXPORT_SYMBOL_GPL(uart_console_device);
2621 static ssize_t uartclk_show(struct device *dev,
2622 struct device_attribute *attr, char *buf)
2624 struct serial_struct tmp;
2625 struct tty_port *port = dev_get_drvdata(dev);
2627 uart_get_info(port, &tmp);
2628 return sprintf(buf, "%d\n", tmp.baud_base * 16);
2631 static ssize_t type_show(struct device *dev,
2632 struct device_attribute *attr, char *buf)
2634 struct serial_struct tmp;
2635 struct tty_port *port = dev_get_drvdata(dev);
2637 uart_get_info(port, &tmp);
2638 return sprintf(buf, "%d\n", tmp.type);
2641 static ssize_t line_show(struct device *dev,
2642 struct device_attribute *attr, char *buf)
2644 struct serial_struct tmp;
2645 struct tty_port *port = dev_get_drvdata(dev);
2647 uart_get_info(port, &tmp);
2648 return sprintf(buf, "%d\n", tmp.line);
2651 static ssize_t port_show(struct device *dev,
2652 struct device_attribute *attr, char *buf)
2654 struct serial_struct tmp;
2655 struct tty_port *port = dev_get_drvdata(dev);
2656 unsigned long ioaddr;
2658 uart_get_info(port, &tmp);
2660 if (HIGH_BITS_OFFSET)
2661 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2662 return sprintf(buf, "0x%lX\n", ioaddr);
2665 static ssize_t irq_show(struct device *dev,
2666 struct device_attribute *attr, char *buf)
2668 struct serial_struct tmp;
2669 struct tty_port *port = dev_get_drvdata(dev);
2671 uart_get_info(port, &tmp);
2672 return sprintf(buf, "%d\n", tmp.irq);
2675 static ssize_t flags_show(struct device *dev,
2676 struct device_attribute *attr, char *buf)
2678 struct serial_struct tmp;
2679 struct tty_port *port = dev_get_drvdata(dev);
2681 uart_get_info(port, &tmp);
2682 return sprintf(buf, "0x%X\n", tmp.flags);
2685 static ssize_t xmit_fifo_size_show(struct device *dev,
2686 struct device_attribute *attr, char *buf)
2688 struct serial_struct tmp;
2689 struct tty_port *port = dev_get_drvdata(dev);
2691 uart_get_info(port, &tmp);
2692 return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2695 static ssize_t close_delay_show(struct device *dev,
2696 struct device_attribute *attr, char *buf)
2698 struct serial_struct tmp;
2699 struct tty_port *port = dev_get_drvdata(dev);
2701 uart_get_info(port, &tmp);
2702 return sprintf(buf, "%d\n", tmp.close_delay);
2705 static ssize_t closing_wait_show(struct device *dev,
2706 struct device_attribute *attr, char *buf)
2708 struct serial_struct tmp;
2709 struct tty_port *port = dev_get_drvdata(dev);
2711 uart_get_info(port, &tmp);
2712 return sprintf(buf, "%d\n", tmp.closing_wait);
2715 static ssize_t custom_divisor_show(struct device *dev,
2716 struct device_attribute *attr, char *buf)
2718 struct serial_struct tmp;
2719 struct tty_port *port = dev_get_drvdata(dev);
2721 uart_get_info(port, &tmp);
2722 return sprintf(buf, "%d\n", tmp.custom_divisor);
2725 static ssize_t io_type_show(struct device *dev,
2726 struct device_attribute *attr, char *buf)
2728 struct serial_struct tmp;
2729 struct tty_port *port = dev_get_drvdata(dev);
2731 uart_get_info(port, &tmp);
2732 return sprintf(buf, "%d\n", tmp.io_type);
2735 static ssize_t iomem_base_show(struct device *dev,
2736 struct device_attribute *attr, char *buf)
2738 struct serial_struct tmp;
2739 struct tty_port *port = dev_get_drvdata(dev);
2741 uart_get_info(port, &tmp);
2742 return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
2745 static ssize_t iomem_reg_shift_show(struct device *dev,
2746 struct device_attribute *attr, char *buf)
2748 struct serial_struct tmp;
2749 struct tty_port *port = dev_get_drvdata(dev);
2751 uart_get_info(port, &tmp);
2752 return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
2755 static ssize_t console_show(struct device *dev,
2756 struct device_attribute *attr, char *buf)
2758 struct tty_port *port = dev_get_drvdata(dev);
2759 struct uart_state *state = container_of(port, struct uart_state, port);
2760 struct uart_port *uport;
2761 bool console = false;
2763 mutex_lock(&port->mutex);
2764 uport = uart_port_check(state);
2766 console = uart_console_enabled(uport);
2767 mutex_unlock(&port->mutex);
2769 return sprintf(buf, "%c\n", console ? 'Y' : 'N');
2772 static ssize_t console_store(struct device *dev,
2773 struct device_attribute *attr, const char *buf, size_t count)
2775 struct tty_port *port = dev_get_drvdata(dev);
2776 struct uart_state *state = container_of(port, struct uart_state, port);
2777 struct uart_port *uport;
2778 bool oldconsole, newconsole;
2781 ret = kstrtobool(buf, &newconsole);
2785 mutex_lock(&port->mutex);
2786 uport = uart_port_check(state);
2788 oldconsole = uart_console_enabled(uport);
2789 if (oldconsole && !newconsole) {
2790 ret = unregister_console(uport->cons);
2791 } else if (!oldconsole && newconsole) {
2792 if (uart_console(uport)) {
2793 uport->console_reinit = 1;
2794 register_console(uport->cons);
2802 mutex_unlock(&port->mutex);
2804 return ret < 0 ? ret : count;
2807 static DEVICE_ATTR_RO(uartclk);
2808 static DEVICE_ATTR_RO(type);
2809 static DEVICE_ATTR_RO(line);
2810 static DEVICE_ATTR_RO(port);
2811 static DEVICE_ATTR_RO(irq);
2812 static DEVICE_ATTR_RO(flags);
2813 static DEVICE_ATTR_RO(xmit_fifo_size);
2814 static DEVICE_ATTR_RO(close_delay);
2815 static DEVICE_ATTR_RO(closing_wait);
2816 static DEVICE_ATTR_RO(custom_divisor);
2817 static DEVICE_ATTR_RO(io_type);
2818 static DEVICE_ATTR_RO(iomem_base);
2819 static DEVICE_ATTR_RO(iomem_reg_shift);
2820 static DEVICE_ATTR_RW(console);
2822 static struct attribute *tty_dev_attrs[] = {
2823 &dev_attr_uartclk.attr,
2824 &dev_attr_type.attr,
2825 &dev_attr_line.attr,
2826 &dev_attr_port.attr,
2828 &dev_attr_flags.attr,
2829 &dev_attr_xmit_fifo_size.attr,
2830 &dev_attr_close_delay.attr,
2831 &dev_attr_closing_wait.attr,
2832 &dev_attr_custom_divisor.attr,
2833 &dev_attr_io_type.attr,
2834 &dev_attr_iomem_base.attr,
2835 &dev_attr_iomem_reg_shift.attr,
2836 &dev_attr_console.attr,
2840 static const struct attribute_group tty_dev_attr_group = {
2841 .attrs = tty_dev_attrs,
2845 * uart_add_one_port - attach a driver-defined port structure
2846 * @drv: pointer to the uart low level driver structure for this port
2847 * @uport: uart port structure to use for this port.
2849 * Context: task context, might sleep
2851 * This allows the driver to register its own uart_port structure
2852 * with the core driver. The main purpose is to allow the low
2853 * level uart drivers to expand uart_port, rather than having yet
2854 * more levels of structures.
2856 int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
2858 struct uart_state *state;
2859 struct tty_port *port;
2861 struct device *tty_dev;
2864 if (uport->line >= drv->nr)
2867 state = drv->state + uport->line;
2868 port = &state->port;
2870 mutex_lock(&port_mutex);
2871 mutex_lock(&port->mutex);
2872 if (state->uart_port) {
2877 /* Link the port to the driver state table and vice versa */
2878 atomic_set(&state->refcount, 1);
2879 init_waitqueue_head(&state->remove_wait);
2880 state->uart_port = uport;
2881 uport->state = state;
2883 state->pm_state = UART_PM_STATE_UNDEFINED;
2884 uport->cons = drv->cons;
2885 uport->minor = drv->tty_driver->minor_start + uport->line;
2886 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
2887 drv->tty_driver->name_base + uport->line);
2894 * If this port is in use as a console then the spinlock is already
2897 if (!uart_console_enabled(uport))
2898 uart_port_spin_lock_init(uport);
2900 if (uport->cons && uport->dev)
2901 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
2903 tty_port_link_device(port, drv->tty_driver, uport->line);
2904 uart_configure_port(drv, state, uport);
2906 port->console = uart_console(uport);
2909 if (uport->attr_group)
2912 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
2914 if (!uport->tty_groups) {
2918 uport->tty_groups[0] = &tty_dev_attr_group;
2919 if (uport->attr_group)
2920 uport->tty_groups[1] = uport->attr_group;
2923 * Register the port whether it's detected or not. This allows
2924 * setserial to be used to alter this port's parameters.
2926 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
2927 uport->line, uport->dev, port, uport->tty_groups);
2928 if (!IS_ERR(tty_dev)) {
2929 device_set_wakeup_capable(tty_dev, 1);
2931 dev_err(uport->dev, "Cannot register tty device on line %d\n",
2936 * Ensure UPF_DEAD is not set.
2938 uport->flags &= ~UPF_DEAD;
2941 mutex_unlock(&port->mutex);
2942 mutex_unlock(&port_mutex);
2948 * uart_remove_one_port - detach a driver defined port structure
2949 * @drv: pointer to the uart low level driver structure for this port
2950 * @uport: uart port structure for this port
2952 * Context: task context, might sleep
2954 * This unhooks (and hangs up) the specified port structure from the
2955 * core driver. No further calls will be made to the low-level code
2958 int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
2960 struct uart_state *state = drv->state + uport->line;
2961 struct tty_port *port = &state->port;
2962 struct uart_port *uart_port;
2963 struct tty_struct *tty;
2966 mutex_lock(&port_mutex);
2969 * Mark the port "dead" - this prevents any opens from
2970 * succeeding while we shut down the port.
2972 mutex_lock(&port->mutex);
2973 uart_port = uart_port_check(state);
2974 if (uart_port != uport)
2975 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
2979 mutex_unlock(&port->mutex);
2983 uport->flags |= UPF_DEAD;
2984 mutex_unlock(&port->mutex);
2987 * Remove the devices from the tty layer
2989 tty_port_unregister_device(port, drv->tty_driver, uport->line);
2991 tty = tty_port_tty_get(port);
2993 tty_vhangup(port->tty);
2998 * If the port is used as a console, unregister it
3000 if (uart_console(uport))
3001 unregister_console(uport->cons);
3004 * Free the port IO and memory resources, if any.
3006 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3007 uport->ops->release_port(uport);
3008 kfree(uport->tty_groups);
3012 * Indicate that there isn't a port here anymore.
3014 uport->type = PORT_UNKNOWN;
3016 mutex_lock(&port->mutex);
3017 WARN_ON(atomic_dec_return(&state->refcount) < 0);
3018 wait_event(state->remove_wait, !atomic_read(&state->refcount));
3019 state->uart_port = NULL;
3020 mutex_unlock(&port->mutex);
3022 mutex_unlock(&port_mutex);
3028 * Are the two ports equivalent?
3030 int uart_match_port(struct uart_port *port1, struct uart_port *port2)
3032 if (port1->iotype != port2->iotype)
3035 switch (port1->iotype) {
3037 return (port1->iobase == port2->iobase);
3039 return (port1->iobase == port2->iobase) &&
3040 (port1->hub6 == port2->hub6);
3047 return (port1->mapbase == port2->mapbase);
3051 EXPORT_SYMBOL(uart_match_port);
3054 * uart_handle_dcd_change - handle a change of carrier detect state
3055 * @uport: uart_port structure for the open port
3056 * @status: new carrier detect status, nonzero if active
3058 * Caller must hold uport->lock
3060 void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
3062 struct tty_port *port = &uport->state->port;
3063 struct tty_struct *tty = port->tty;
3064 struct tty_ldisc *ld;
3066 lockdep_assert_held_once(&uport->lock);
3069 ld = tty_ldisc_ref(tty);
3071 if (ld->ops->dcd_change)
3072 ld->ops->dcd_change(tty, status);
3073 tty_ldisc_deref(ld);
3077 uport->icount.dcd++;
3079 if (uart_dcd_enabled(uport)) {
3081 wake_up_interruptible(&port->open_wait);
3086 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3089 * uart_handle_cts_change - handle a change of clear-to-send state
3090 * @uport: uart_port structure for the open port
3091 * @status: new clear to send status, nonzero if active
3093 * Caller must hold uport->lock
3095 void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
3097 lockdep_assert_held_once(&uport->lock);
3099 uport->icount.cts++;
3101 if (uart_softcts_mode(uport)) {
3102 if (uport->hw_stopped) {
3104 uport->hw_stopped = 0;
3105 uport->ops->start_tx(uport);
3106 uart_write_wakeup(uport);
3110 uport->hw_stopped = 1;
3111 uport->ops->stop_tx(uport);
3117 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3120 * uart_insert_char - push a char to the uart layer
3122 * User is responsible to call tty_flip_buffer_push when they are done with
3125 * @port: corresponding port
3126 * @status: state of the serial port RX buffer (LSR for 8250)
3127 * @overrun: mask of overrun bits in @status
3128 * @ch: character to push
3129 * @flag: flag for the character (see TTY_NORMAL and friends)
3131 void uart_insert_char(struct uart_port *port, unsigned int status,
3132 unsigned int overrun, unsigned int ch, unsigned int flag)
3134 struct tty_port *tport = &port->state->port;
3136 if ((status & port->ignore_status_mask & ~overrun) == 0)
3137 if (tty_insert_flip_char(tport, ch, flag) == 0)
3138 ++port->icount.buf_overrun;
3141 * Overrun is special. Since it's reported immediately,
3142 * it doesn't affect the current character.
3144 if (status & ~port->ignore_status_mask & overrun)
3145 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3146 ++port->icount.buf_overrun;
3148 EXPORT_SYMBOL_GPL(uart_insert_char);
3150 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3151 static const char sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3153 static void uart_sysrq_on(struct work_struct *w)
3155 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3157 sysrq_toggle_support(1);
3158 pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3159 sysrq_toggle_seq_len, sysrq_toggle_seq);
3161 static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3164 * uart_try_toggle_sysrq - Enables SysRq from serial line
3165 * @port: uart_port structure where char(s) after BREAK met
3166 * @ch: new character in the sequence after received BREAK
3168 * Enables magic SysRq when the required sequence is met on port
3169 * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3171 * Returns false if @ch is out of enabling sequence and should be
3172 * handled some other way, true if @ch was consumed.
3174 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
3176 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3178 if (!sysrq_toggle_seq_len)
3181 BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3182 if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3183 port->sysrq_seq = 0;
3187 if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3188 port->sysrq = jiffies + SYSRQ_TIMEOUT;
3192 schedule_work(&sysrq_enable_work);
3197 EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3200 EXPORT_SYMBOL(uart_write_wakeup);
3201 EXPORT_SYMBOL(uart_register_driver);
3202 EXPORT_SYMBOL(uart_unregister_driver);
3203 EXPORT_SYMBOL(uart_suspend_port);
3204 EXPORT_SYMBOL(uart_resume_port);
3205 EXPORT_SYMBOL(uart_add_one_port);
3206 EXPORT_SYMBOL(uart_remove_one_port);
3209 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3210 * @port: uart device's target port
3212 * This function implements the device tree binding described in
3213 * Documentation/devicetree/bindings/serial/rs485.txt.
3215 int uart_get_rs485_mode(struct uart_port *port)
3217 struct serial_rs485 *rs485conf = &port->rs485;
3218 struct device *dev = port->dev;
3222 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3225 rs485conf->delay_rts_before_send = rs485_delay[0];
3226 rs485conf->delay_rts_after_send = rs485_delay[1];
3228 rs485conf->delay_rts_before_send = 0;
3229 rs485conf->delay_rts_after_send = 0;
3233 * Clear full-duplex and enabled flags, set RTS polarity to active high
3234 * to get to a defined state with the following properties:
3236 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3237 SER_RS485_TERMINATE_BUS |
3238 SER_RS485_RTS_AFTER_SEND);
3239 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3241 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3242 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3244 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3245 rs485conf->flags |= SER_RS485_ENABLED;
3247 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3248 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3249 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3253 * Disabling termination by default is the safe choice: Else if many
3254 * bus participants enable it, no communication is possible at all.
3255 * Works fine for short cables and users may enable for longer cables.
3257 port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
3259 if (IS_ERR(port->rs485_term_gpio)) {
3260 ret = PTR_ERR(port->rs485_term_gpio);
3261 port->rs485_term_gpio = NULL;
3262 return dev_err_probe(dev, ret, "Cannot get rs485-term-gpios\n");
3267 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3269 MODULE_DESCRIPTION("Serial driver core");
3270 MODULE_LICENSE("GPL");