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>
18 #include <linux/proc_fs.h>
19 #include <linux/seq_file.h>
20 #include <linux/device.h>
21 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
22 #include <linux/serial_core.h>
23 #include <linux/delay.h>
24 #include <linux/mutex.h>
26 #include <linux/irq.h>
27 #include <linux/uaccess.h>
30 * This is used to lock changes in serial line configuration.
32 static DEFINE_MUTEX(port_mutex);
35 * lockdep: port->lock is initialized in two places, but we
36 * want only one lock-class:
38 static struct lock_class_key port_lock_key;
40 #define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
42 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
43 struct ktermios *old_termios);
44 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
45 static void uart_change_pm(struct uart_state *state,
46 enum uart_pm_state pm_state);
48 static void uart_port_shutdown(struct tty_port *port);
50 static int uart_dcd_enabled(struct uart_port *uport)
52 return !!(uport->status & UPSTAT_DCD_ENABLE);
55 static inline struct uart_port *uart_port_ref(struct uart_state *state)
57 if (atomic_add_unless(&state->refcount, 1, 0))
58 return state->uart_port;
62 static inline void uart_port_deref(struct uart_port *uport)
64 if (atomic_dec_and_test(&uport->state->refcount))
65 wake_up(&uport->state->remove_wait);
68 #define uart_port_lock(state, flags) \
70 struct uart_port *__uport = uart_port_ref(state); \
72 spin_lock_irqsave(&__uport->lock, flags); \
76 #define uart_port_unlock(uport, flags) \
78 struct uart_port *__uport = uport; \
80 spin_unlock_irqrestore(&__uport->lock, flags); \
81 uart_port_deref(__uport); \
85 static inline struct uart_port *uart_port_check(struct uart_state *state)
87 lockdep_assert_held(&state->port.mutex);
88 return state->uart_port;
92 * This routine is used by the interrupt handler to schedule processing in
93 * the software interrupt portion of the driver.
95 void uart_write_wakeup(struct uart_port *port)
97 struct uart_state *state = port->state;
99 * This means you called this function _after_ the port was
100 * closed. No cookie for you.
103 tty_port_tty_wakeup(&state->port);
106 static void uart_stop(struct tty_struct *tty)
108 struct uart_state *state = tty->driver_data;
109 struct uart_port *port;
112 port = uart_port_lock(state, flags);
114 port->ops->stop_tx(port);
115 uart_port_unlock(port, flags);
118 static void __uart_start(struct tty_struct *tty)
120 struct uart_state *state = tty->driver_data;
121 struct uart_port *port = state->uart_port;
123 if (port && !uart_tx_stopped(port))
124 port->ops->start_tx(port);
127 static void uart_start(struct tty_struct *tty)
129 struct uart_state *state = tty->driver_data;
130 struct uart_port *port;
133 port = uart_port_lock(state, flags);
135 uart_port_unlock(port, flags);
139 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
144 spin_lock_irqsave(&port->lock, flags);
146 port->mctrl = (old & ~clear) | set;
147 if (old != port->mctrl)
148 port->ops->set_mctrl(port, port->mctrl);
149 spin_unlock_irqrestore(&port->lock, flags);
152 #define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
153 #define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
155 static void uart_port_dtr_rts(struct uart_port *uport, int raise)
157 int rs485_on = uport->rs485_config &&
158 (uport->rs485.flags & SER_RS485_ENABLED);
159 int RTS_after_send = !!(uport->rs485.flags & SER_RS485_RTS_AFTER_SEND);
162 if (rs485_on && !RTS_after_send) {
163 uart_set_mctrl(uport, TIOCM_DTR);
164 uart_clear_mctrl(uport, TIOCM_RTS);
166 uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
169 unsigned int clear = TIOCM_DTR;
171 clear |= (!rs485_on || !RTS_after_send) ? TIOCM_RTS : 0;
172 uart_clear_mctrl(uport, clear);
177 * Startup the port. This will be called once per open. All calls
178 * will be serialised by the per-port mutex.
180 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
183 struct uart_port *uport = uart_port_check(state);
185 unsigned long flags = 0;
188 if (uport->type == PORT_UNKNOWN)
192 * Make sure the device is in D0 state.
194 uart_change_pm(state, UART_PM_STATE_ON);
197 * Initialise and allocate the transmit and temporary
200 page = get_zeroed_page(GFP_KERNEL);
204 uart_port_lock(state, flags);
205 if (!state->xmit.buf) {
206 state->xmit.buf = (unsigned char *) page;
207 uart_circ_clear(&state->xmit);
211 uart_port_unlock(uport, flags);
213 retval = uport->ops->startup(uport);
215 if (uart_console(uport) && uport->cons->cflag) {
216 tty->termios.c_cflag = uport->cons->cflag;
217 uport->cons->cflag = 0;
220 * Initialise the hardware port settings.
222 uart_change_speed(tty, state, NULL);
225 * Setup the RTS and DTR signals once the
226 * port is open and ready to respond.
228 if (init_hw && C_BAUD(tty))
229 uart_port_dtr_rts(uport, 1);
233 * This is to allow setserial on this port. People may want to set
234 * port/irq/type and then reconfigure the port properly if it failed
237 if (retval && capable(CAP_SYS_ADMIN))
243 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
246 struct tty_port *port = &state->port;
249 if (tty_port_initialized(port))
252 retval = uart_port_startup(tty, state, init_hw);
254 set_bit(TTY_IO_ERROR, &tty->flags);
260 * This routine will shutdown a serial port; interrupts are disabled, and
261 * DTR is dropped if the hangup on close termio flag is on. Calls to
262 * uart_shutdown are serialised by the per-port semaphore.
264 * uport == NULL if uart_port has already been removed
266 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
268 struct uart_port *uport = uart_port_check(state);
269 struct tty_port *port = &state->port;
270 unsigned long flags = 0;
273 * Set the TTY IO error marker
276 set_bit(TTY_IO_ERROR, &tty->flags);
278 if (tty_port_initialized(port)) {
279 tty_port_set_initialized(port, 0);
282 * Turn off DTR and RTS early.
284 if (uport && uart_console(uport) && tty)
285 uport->cons->cflag = tty->termios.c_cflag;
287 if (!tty || C_HUPCL(tty))
288 uart_port_dtr_rts(uport, 0);
290 uart_port_shutdown(port);
294 * It's possible for shutdown to be called after suspend if we get
295 * a DCD drop (hangup) at just the right time. Clear suspended bit so
296 * we don't try to resume a port that has been shutdown.
298 tty_port_set_suspended(port, 0);
301 * Free the transmit buffer page.
303 uart_port_lock(state, flags);
304 if (state->xmit.buf) {
305 free_page((unsigned long)state->xmit.buf);
306 state->xmit.buf = NULL;
308 uart_port_unlock(uport, flags);
312 * uart_update_timeout - update per-port FIFO timeout.
313 * @port: uart_port structure describing the port
314 * @cflag: termios cflag value
315 * @baud: speed of the port
317 * Set the port FIFO timeout value. The @cflag value should
318 * reflect the actual hardware settings.
321 uart_update_timeout(struct uart_port *port, unsigned int cflag,
326 /* byte size and parity */
327 switch (cflag & CSIZE) {
348 * The total number of bits to be transmitted in the fifo.
350 bits = bits * port->fifosize;
353 * Figure the timeout to send the above number of bits.
354 * Add .02 seconds of slop
356 port->timeout = (HZ * bits) / baud + HZ/50;
359 EXPORT_SYMBOL(uart_update_timeout);
362 * uart_get_baud_rate - return baud rate for a particular port
363 * @port: uart_port structure describing the port in question.
364 * @termios: desired termios settings.
365 * @old: old termios (or NULL)
366 * @min: minimum acceptable baud rate
367 * @max: maximum acceptable baud rate
369 * Decode the termios structure into a numeric baud rate,
370 * taking account of the magic 38400 baud rate (with spd_*
371 * flags), and mapping the %B0 rate to 9600 baud.
373 * If the new baud rate is invalid, try the old termios setting.
374 * If it's still invalid, we try 9600 baud.
376 * Update the @termios structure to reflect the baud rate
377 * we're actually going to be using. Don't do this for the case
378 * where B0 is requested ("hang up").
381 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
382 struct ktermios *old, unsigned int min, unsigned int max)
386 unsigned int altbaud;
388 upf_t flags = port->flags & UPF_SPD_MASK;
408 for (try = 0; try < 2; try++) {
409 baud = tty_termios_baud_rate(termios);
412 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
415 if (try == 0 && baud == 38400)
419 * Special case: B0 rate.
426 if (baud >= min && baud <= max)
430 * Oops, the quotient was zero. Try again with
431 * the old baud rate if possible.
433 termios->c_cflag &= ~CBAUD;
435 baud = tty_termios_baud_rate(old);
437 tty_termios_encode_baud_rate(termios,
444 * As a last resort, if the range cannot be met then clip to
445 * the nearest chip supported rate.
449 tty_termios_encode_baud_rate(termios,
452 tty_termios_encode_baud_rate(termios,
456 /* Should never happen */
461 EXPORT_SYMBOL(uart_get_baud_rate);
464 * uart_get_divisor - return uart clock divisor
465 * @port: uart_port structure describing the port.
466 * @baud: desired baud rate
468 * Calculate the uart clock divisor for the port.
471 uart_get_divisor(struct uart_port *port, unsigned int baud)
476 * Old custom speed handling.
478 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
479 quot = port->custom_divisor;
481 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
486 EXPORT_SYMBOL(uart_get_divisor);
488 /* Caller holds port mutex */
489 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
490 struct ktermios *old_termios)
492 struct uart_port *uport = uart_port_check(state);
493 struct ktermios *termios;
497 * If we have no tty, termios, or the port does not exist,
498 * then we can't set the parameters for this port.
500 if (!tty || uport->type == PORT_UNKNOWN)
503 termios = &tty->termios;
504 uport->ops->set_termios(uport, termios, old_termios);
507 * Set modem status enables based on termios cflag
509 spin_lock_irq(&uport->lock);
510 if (termios->c_cflag & CRTSCTS)
511 uport->status |= UPSTAT_CTS_ENABLE;
513 uport->status &= ~UPSTAT_CTS_ENABLE;
515 if (termios->c_cflag & CLOCAL)
516 uport->status &= ~UPSTAT_DCD_ENABLE;
518 uport->status |= UPSTAT_DCD_ENABLE;
520 /* reset sw-assisted CTS flow control based on (possibly) new mode */
521 hw_stopped = uport->hw_stopped;
522 uport->hw_stopped = uart_softcts_mode(uport) &&
523 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
524 if (uport->hw_stopped) {
526 uport->ops->stop_tx(uport);
531 spin_unlock_irq(&uport->lock);
534 static int uart_put_char(struct tty_struct *tty, unsigned char c)
536 struct uart_state *state = tty->driver_data;
537 struct uart_port *port;
538 struct circ_buf *circ;
546 port = uart_port_lock(state, flags);
547 if (port && uart_circ_chars_free(circ) != 0) {
548 circ->buf[circ->head] = c;
549 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
552 uart_port_unlock(port, flags);
556 static void uart_flush_chars(struct tty_struct *tty)
561 static int uart_write(struct tty_struct *tty,
562 const unsigned char *buf, int count)
564 struct uart_state *state = tty->driver_data;
565 struct uart_port *port;
566 struct circ_buf *circ;
571 * This means you called this function _after_ the port was
572 * closed. No cookie for you.
583 port = uart_port_lock(state, 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 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 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;
745 memset(retinfo, 0, sizeof(*retinfo));
748 * Ensure the state we copy is consistent and no hardware changes
751 mutex_lock(&port->mutex);
752 uport = uart_port_check(state);
756 retinfo->type = uport->type;
757 retinfo->line = uport->line;
758 retinfo->port = uport->iobase;
759 if (HIGH_BITS_OFFSET)
760 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
761 retinfo->irq = uport->irq;
762 retinfo->flags = (__force int)uport->flags;
763 retinfo->xmit_fifo_size = uport->fifosize;
764 retinfo->baud_base = uport->uartclk / 16;
765 retinfo->close_delay = jiffies_to_msecs(port->close_delay) / 10;
766 retinfo->closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
767 ASYNC_CLOSING_WAIT_NONE :
768 jiffies_to_msecs(port->closing_wait) / 10;
769 retinfo->custom_divisor = uport->custom_divisor;
770 retinfo->hub6 = uport->hub6;
771 retinfo->io_type = uport->iotype;
772 retinfo->iomem_reg_shift = uport->regshift;
773 retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
777 mutex_unlock(&port->mutex);
781 static int uart_get_info_user(struct tty_struct *tty,
782 struct serial_struct *ss)
784 struct uart_state *state = tty->driver_data;
785 struct tty_port *port = &state->port;
787 return uart_get_info(port, ss) < 0 ? -EIO : 0;
790 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
791 struct uart_state *state,
792 struct serial_struct *new_info)
794 struct uart_port *uport = uart_port_check(state);
795 unsigned long new_port;
796 unsigned int change_irq, change_port, closing_wait;
797 unsigned int old_custom_divisor, close_delay;
798 upf_t old_flags, new_flags;
804 new_port = new_info->port;
805 if (HIGH_BITS_OFFSET)
806 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
808 new_info->irq = irq_canonicalize(new_info->irq);
809 close_delay = msecs_to_jiffies(new_info->close_delay * 10);
810 closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
811 ASYNC_CLOSING_WAIT_NONE :
812 msecs_to_jiffies(new_info->closing_wait * 10);
815 change_irq = !(uport->flags & UPF_FIXED_PORT)
816 && new_info->irq != uport->irq;
819 * Since changing the 'type' of the port changes its resource
820 * allocations, we should treat type changes the same as
823 change_port = !(uport->flags & UPF_FIXED_PORT)
824 && (new_port != uport->iobase ||
825 (unsigned long)new_info->iomem_base != uport->mapbase ||
826 new_info->hub6 != uport->hub6 ||
827 new_info->io_type != uport->iotype ||
828 new_info->iomem_reg_shift != uport->regshift ||
829 new_info->type != uport->type);
831 old_flags = uport->flags;
832 new_flags = (__force upf_t)new_info->flags;
833 old_custom_divisor = uport->custom_divisor;
835 if (!capable(CAP_SYS_ADMIN)) {
837 if (change_irq || change_port ||
838 (new_info->baud_base != uport->uartclk / 16) ||
839 (close_delay != port->close_delay) ||
840 (closing_wait != port->closing_wait) ||
841 (new_info->xmit_fifo_size &&
842 new_info->xmit_fifo_size != uport->fifosize) ||
843 (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
845 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
846 (new_flags & UPF_USR_MASK));
847 uport->custom_divisor = new_info->custom_divisor;
852 * Ask the low level driver to verify the settings.
854 if (uport->ops->verify_port)
855 retval = uport->ops->verify_port(uport, new_info);
857 if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
858 (new_info->baud_base < 9600))
864 if (change_port || change_irq) {
868 * Make sure that we are the sole user of this port.
870 if (tty_port_users(port) > 1)
874 * We need to shutdown the serial port at the old
875 * port/type/irq combination.
877 uart_shutdown(tty, state);
881 unsigned long old_iobase, old_mapbase;
882 unsigned int old_type, old_iotype, old_hub6, old_shift;
884 old_iobase = uport->iobase;
885 old_mapbase = uport->mapbase;
886 old_type = uport->type;
887 old_hub6 = uport->hub6;
888 old_iotype = uport->iotype;
889 old_shift = uport->regshift;
892 * Free and release old regions
894 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
895 uport->ops->release_port(uport);
897 uport->iobase = new_port;
898 uport->type = new_info->type;
899 uport->hub6 = new_info->hub6;
900 uport->iotype = new_info->io_type;
901 uport->regshift = new_info->iomem_reg_shift;
902 uport->mapbase = (unsigned long)new_info->iomem_base;
905 * Claim and map the new regions
907 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
908 retval = uport->ops->request_port(uport);
910 /* Always success - Jean II */
915 * If we fail to request resources for the
916 * new port, try to restore the old settings.
919 uport->iobase = old_iobase;
920 uport->type = old_type;
921 uport->hub6 = old_hub6;
922 uport->iotype = old_iotype;
923 uport->regshift = old_shift;
924 uport->mapbase = old_mapbase;
926 if (old_type != PORT_UNKNOWN) {
927 retval = uport->ops->request_port(uport);
929 * If we failed to restore the old settings,
933 uport->type = PORT_UNKNOWN;
941 /* Added to return the correct error -Ram Gupta */
947 uport->irq = new_info->irq;
948 if (!(uport->flags & UPF_FIXED_PORT))
949 uport->uartclk = new_info->baud_base * 16;
950 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
951 (new_flags & UPF_CHANGE_MASK);
952 uport->custom_divisor = new_info->custom_divisor;
953 port->close_delay = close_delay;
954 port->closing_wait = closing_wait;
955 if (new_info->xmit_fifo_size)
956 uport->fifosize = new_info->xmit_fifo_size;
957 port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
961 if (uport->type == PORT_UNKNOWN)
963 if (tty_port_initialized(port)) {
964 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
965 old_custom_divisor != uport->custom_divisor) {
967 * If they're setting up a custom divisor or speed,
968 * instead of clearing it, then bitch about it.
970 if (uport->flags & UPF_SPD_MASK) {
971 dev_notice_ratelimited(uport->dev,
972 "%s sets custom speed on %s. This is deprecated.\n",
974 tty_name(port->tty));
976 uart_change_speed(tty, state, NULL);
979 retval = uart_startup(tty, state, 1);
981 tty_port_set_initialized(port, true);
989 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
991 struct uart_state *state = tty->driver_data;
992 struct tty_port *port = &state->port;
995 down_write(&tty->termios_rwsem);
997 * This semaphore protects port->count. It is also
998 * very useful to prevent opens. Also, take the
999 * port configuration semaphore to make sure that a
1000 * module insertion/removal doesn't change anything
1003 mutex_lock(&port->mutex);
1004 retval = uart_set_info(tty, port, state, ss);
1005 mutex_unlock(&port->mutex);
1006 up_write(&tty->termios_rwsem);
1011 * uart_get_lsr_info - get line status register info
1012 * @tty: tty associated with the UART
1013 * @state: UART being queried
1014 * @value: returned modem value
1016 static int uart_get_lsr_info(struct tty_struct *tty,
1017 struct uart_state *state, unsigned int __user *value)
1019 struct uart_port *uport = uart_port_check(state);
1020 unsigned int result;
1022 result = uport->ops->tx_empty(uport);
1025 * If we're about to load something into the transmit
1026 * register, we'll pretend the transmitter isn't empty to
1027 * avoid a race condition (depending on when the transmit
1028 * interrupt happens).
1030 if (uport->x_char ||
1031 ((uart_circ_chars_pending(&state->xmit) > 0) &&
1032 !uart_tx_stopped(uport)))
1033 result &= ~TIOCSER_TEMT;
1035 return put_user(result, value);
1038 static int uart_tiocmget(struct tty_struct *tty)
1040 struct uart_state *state = tty->driver_data;
1041 struct tty_port *port = &state->port;
1042 struct uart_port *uport;
1045 mutex_lock(&port->mutex);
1046 uport = uart_port_check(state);
1050 if (!tty_io_error(tty)) {
1051 result = uport->mctrl;
1052 spin_lock_irq(&uport->lock);
1053 result |= uport->ops->get_mctrl(uport);
1054 spin_unlock_irq(&uport->lock);
1057 mutex_unlock(&port->mutex);
1062 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1064 struct uart_state *state = tty->driver_data;
1065 struct tty_port *port = &state->port;
1066 struct uart_port *uport;
1069 mutex_lock(&port->mutex);
1070 uport = uart_port_check(state);
1074 if (!tty_io_error(tty)) {
1075 uart_update_mctrl(uport, set, clear);
1079 mutex_unlock(&port->mutex);
1083 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1085 struct uart_state *state = tty->driver_data;
1086 struct tty_port *port = &state->port;
1087 struct uart_port *uport;
1090 mutex_lock(&port->mutex);
1091 uport = uart_port_check(state);
1095 if (uport->type != PORT_UNKNOWN)
1096 uport->ops->break_ctl(uport, break_state);
1099 mutex_unlock(&port->mutex);
1103 static int uart_do_autoconfig(struct tty_struct *tty,struct uart_state *state)
1105 struct tty_port *port = &state->port;
1106 struct uart_port *uport;
1109 if (!capable(CAP_SYS_ADMIN))
1113 * Take the per-port semaphore. This prevents count from
1114 * changing, and hence any extra opens of the port while
1115 * we're auto-configuring.
1117 if (mutex_lock_interruptible(&port->mutex))
1118 return -ERESTARTSYS;
1120 uport = uart_port_check(state);
1127 if (tty_port_users(port) == 1) {
1128 uart_shutdown(tty, state);
1131 * If we already have a port type configured,
1132 * we must release its resources.
1134 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1135 uport->ops->release_port(uport);
1137 flags = UART_CONFIG_TYPE;
1138 if (uport->flags & UPF_AUTO_IRQ)
1139 flags |= UART_CONFIG_IRQ;
1142 * This will claim the ports resources if
1145 uport->ops->config_port(uport, flags);
1147 ret = uart_startup(tty, state, 1);
1149 tty_port_set_initialized(port, true);
1154 mutex_unlock(&port->mutex);
1158 static void uart_enable_ms(struct uart_port *uport)
1161 * Force modem status interrupts on
1163 if (uport->ops->enable_ms)
1164 uport->ops->enable_ms(uport);
1168 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1169 * - mask passed in arg for lines of interest
1170 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1171 * Caller should use TIOCGICOUNT to see which one it was
1173 * FIXME: This wants extracting into a common all driver implementation
1174 * of TIOCMWAIT using tty_port.
1176 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1178 struct uart_port *uport;
1179 struct tty_port *port = &state->port;
1180 DECLARE_WAITQUEUE(wait, current);
1181 struct uart_icount cprev, cnow;
1185 * note the counters on entry
1187 uport = uart_port_ref(state);
1190 spin_lock_irq(&uport->lock);
1191 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1192 uart_enable_ms(uport);
1193 spin_unlock_irq(&uport->lock);
1195 add_wait_queue(&port->delta_msr_wait, &wait);
1197 spin_lock_irq(&uport->lock);
1198 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1199 spin_unlock_irq(&uport->lock);
1201 set_current_state(TASK_INTERRUPTIBLE);
1203 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1204 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1205 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1206 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1213 /* see if a signal did it */
1214 if (signal_pending(current)) {
1221 __set_current_state(TASK_RUNNING);
1222 remove_wait_queue(&port->delta_msr_wait, &wait);
1223 uart_port_deref(uport);
1229 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1230 * Return: write counters to the user passed counter struct
1231 * NB: both 1->0 and 0->1 transitions are counted except for
1232 * RI where only 0->1 is counted.
1234 static int uart_get_icount(struct tty_struct *tty,
1235 struct serial_icounter_struct *icount)
1237 struct uart_state *state = tty->driver_data;
1238 struct uart_icount cnow;
1239 struct uart_port *uport;
1241 uport = uart_port_ref(state);
1244 spin_lock_irq(&uport->lock);
1245 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1246 spin_unlock_irq(&uport->lock);
1247 uart_port_deref(uport);
1249 icount->cts = cnow.cts;
1250 icount->dsr = cnow.dsr;
1251 icount->rng = cnow.rng;
1252 icount->dcd = cnow.dcd;
1253 icount->rx = cnow.rx;
1254 icount->tx = cnow.tx;
1255 icount->frame = cnow.frame;
1256 icount->overrun = cnow.overrun;
1257 icount->parity = cnow.parity;
1258 icount->brk = cnow.brk;
1259 icount->buf_overrun = cnow.buf_overrun;
1264 static int uart_get_rs485_config(struct uart_port *port,
1265 struct serial_rs485 __user *rs485)
1267 unsigned long flags;
1268 struct serial_rs485 aux;
1270 spin_lock_irqsave(&port->lock, flags);
1272 spin_unlock_irqrestore(&port->lock, flags);
1274 if (copy_to_user(rs485, &aux, sizeof(aux)))
1280 static int uart_set_rs485_config(struct uart_port *port,
1281 struct serial_rs485 __user *rs485_user)
1283 struct serial_rs485 rs485;
1285 unsigned long flags;
1287 if (!port->rs485_config)
1288 return -ENOIOCTLCMD;
1290 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1293 spin_lock_irqsave(&port->lock, flags);
1294 ret = port->rs485_config(port, &rs485);
1295 spin_unlock_irqrestore(&port->lock, flags);
1299 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1305 static int uart_get_iso7816_config(struct uart_port *port,
1306 struct serial_iso7816 __user *iso7816)
1308 unsigned long flags;
1309 struct serial_iso7816 aux;
1311 if (!port->iso7816_config)
1312 return -ENOIOCTLCMD;
1314 spin_lock_irqsave(&port->lock, flags);
1315 aux = port->iso7816;
1316 spin_unlock_irqrestore(&port->lock, flags);
1318 if (copy_to_user(iso7816, &aux, sizeof(aux)))
1324 static int uart_set_iso7816_config(struct uart_port *port,
1325 struct serial_iso7816 __user *iso7816_user)
1327 struct serial_iso7816 iso7816;
1329 unsigned long flags;
1331 if (!port->iso7816_config)
1332 return -ENOIOCTLCMD;
1334 if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1338 * There are 5 words reserved for future use. Check that userspace
1339 * doesn't put stuff in there to prevent breakages in the future.
1341 for (i = 0; i < 5; i++)
1342 if (iso7816.reserved[i])
1345 spin_lock_irqsave(&port->lock, flags);
1346 ret = port->iso7816_config(port, &iso7816);
1347 spin_unlock_irqrestore(&port->lock, flags);
1351 if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1358 * Called via sys_ioctl. We can use spin_lock_irq() here.
1361 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1363 struct uart_state *state = tty->driver_data;
1364 struct tty_port *port = &state->port;
1365 struct uart_port *uport;
1366 void __user *uarg = (void __user *)arg;
1367 int ret = -ENOIOCTLCMD;
1371 * These ioctls don't rely on the hardware to be present.
1375 down_write(&tty->termios_rwsem);
1376 ret = uart_do_autoconfig(tty, state);
1377 up_write(&tty->termios_rwsem);
1381 if (ret != -ENOIOCTLCMD)
1384 if (tty_io_error(tty)) {
1390 * The following should only be used when hardware is present.
1394 ret = uart_wait_modem_status(state, arg);
1398 if (ret != -ENOIOCTLCMD)
1401 mutex_lock(&port->mutex);
1402 uport = uart_port_check(state);
1404 if (!uport || tty_io_error(tty)) {
1410 * All these rely on hardware being present and need to be
1411 * protected against the tty being hung up.
1415 case TIOCSERGETLSR: /* Get line status register */
1416 ret = uart_get_lsr_info(tty, state, uarg);
1420 ret = uart_get_rs485_config(uport, uarg);
1424 ret = uart_set_rs485_config(uport, uarg);
1428 ret = uart_set_iso7816_config(state->uart_port, uarg);
1432 ret = uart_get_iso7816_config(state->uart_port, uarg);
1435 if (uport->ops->ioctl)
1436 ret = uport->ops->ioctl(uport, cmd, arg);
1440 mutex_unlock(&port->mutex);
1445 static void uart_set_ldisc(struct tty_struct *tty)
1447 struct uart_state *state = tty->driver_data;
1448 struct uart_port *uport;
1450 mutex_lock(&state->port.mutex);
1451 uport = uart_port_check(state);
1452 if (uport && uport->ops->set_ldisc)
1453 uport->ops->set_ldisc(uport, &tty->termios);
1454 mutex_unlock(&state->port.mutex);
1457 static void uart_set_termios(struct tty_struct *tty,
1458 struct ktermios *old_termios)
1460 struct uart_state *state = tty->driver_data;
1461 struct uart_port *uport;
1462 unsigned int cflag = tty->termios.c_cflag;
1463 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1464 bool sw_changed = false;
1466 mutex_lock(&state->port.mutex);
1467 uport = uart_port_check(state);
1472 * Drivers doing software flow control also need to know
1473 * about changes to these input settings.
1475 if (uport->flags & UPF_SOFT_FLOW) {
1476 iflag_mask |= IXANY|IXON|IXOFF;
1478 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1479 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1483 * These are the bits that are used to setup various
1484 * flags in the low level driver. We can ignore the Bfoo
1485 * bits in c_cflag; c_[io]speed will always be set
1486 * appropriately by set_termios() in tty_ioctl.c
1488 if ((cflag ^ old_termios->c_cflag) == 0 &&
1489 tty->termios.c_ospeed == old_termios->c_ospeed &&
1490 tty->termios.c_ispeed == old_termios->c_ispeed &&
1491 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1496 uart_change_speed(tty, state, old_termios);
1497 /* reload cflag from termios; port driver may have overriden flags */
1498 cflag = tty->termios.c_cflag;
1500 /* Handle transition to B0 status */
1501 if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1502 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1503 /* Handle transition away from B0 status */
1504 else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1505 unsigned int mask = TIOCM_DTR;
1506 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1508 uart_set_mctrl(uport, mask);
1511 mutex_unlock(&state->port.mutex);
1515 * Calls to uart_close() are serialised via the tty_lock in
1516 * drivers/tty/tty_io.c:tty_release()
1517 * drivers/tty/tty_io.c:do_tty_hangup()
1519 static void uart_close(struct tty_struct *tty, struct file *filp)
1521 struct uart_state *state = tty->driver_data;
1524 struct uart_driver *drv = tty->driver->driver_state;
1525 struct tty_port *port;
1527 state = drv->state + tty->index;
1528 port = &state->port;
1529 spin_lock_irq(&port->lock);
1531 spin_unlock_irq(&port->lock);
1535 pr_debug("uart_close(%d) called\n", tty->index);
1537 tty_port_close(tty->port, tty, filp);
1540 static void uart_tty_port_shutdown(struct tty_port *port)
1542 struct uart_state *state = container_of(port, struct uart_state, port);
1543 struct uart_port *uport = uart_port_check(state);
1546 * At this point, we stop accepting input. To do this, we
1547 * disable the receive line status interrupts.
1549 if (WARN(!uport, "detached port still initialized!\n"))
1552 spin_lock_irq(&uport->lock);
1553 uport->ops->stop_rx(uport);
1554 spin_unlock_irq(&uport->lock);
1556 uart_port_shutdown(port);
1559 * It's possible for shutdown to be called after suspend if we get
1560 * a DCD drop (hangup) at just the right time. Clear suspended bit so
1561 * we don't try to resume a port that has been shutdown.
1563 tty_port_set_suspended(port, 0);
1565 uart_change_pm(state, UART_PM_STATE_OFF);
1569 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1571 struct uart_state *state = tty->driver_data;
1572 struct uart_port *port;
1573 unsigned long char_time, expire;
1575 port = uart_port_ref(state);
1579 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1580 uart_port_deref(port);
1585 * Set the check interval to be 1/5 of the estimated time to
1586 * send a single character, and make it at least 1. The check
1587 * interval should also be less than the timeout.
1589 * Note: we have to use pretty tight timings here to satisfy
1592 char_time = (port->timeout - HZ/50) / port->fifosize;
1593 char_time = char_time / 5;
1596 if (timeout && timeout < char_time)
1597 char_time = timeout;
1600 * If the transmitter hasn't cleared in twice the approximate
1601 * amount of time to send the entire FIFO, it probably won't
1602 * ever clear. This assumes the UART isn't doing flow
1603 * control, which is currently the case. Hence, if it ever
1604 * takes longer than port->timeout, this is probably due to a
1605 * UART bug of some kind. So, we clamp the timeout parameter at
1608 if (timeout == 0 || timeout > 2 * port->timeout)
1609 timeout = 2 * port->timeout;
1611 expire = jiffies + timeout;
1613 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1614 port->line, jiffies, expire);
1617 * Check whether the transmitter is empty every 'char_time'.
1618 * 'timeout' / 'expire' give us the maximum amount of time
1621 while (!port->ops->tx_empty(port)) {
1622 msleep_interruptible(jiffies_to_msecs(char_time));
1623 if (signal_pending(current))
1625 if (time_after(jiffies, expire))
1628 uart_port_deref(port);
1632 * Calls to uart_hangup() are serialised by the tty_lock in
1633 * drivers/tty/tty_io.c:do_tty_hangup()
1634 * This runs from a workqueue and can sleep for a _short_ time only.
1636 static void uart_hangup(struct tty_struct *tty)
1638 struct uart_state *state = tty->driver_data;
1639 struct tty_port *port = &state->port;
1640 struct uart_port *uport;
1641 unsigned long flags;
1643 pr_debug("uart_hangup(%d)\n", tty->index);
1645 mutex_lock(&port->mutex);
1646 uport = uart_port_check(state);
1647 WARN(!uport, "hangup of detached port!\n");
1649 if (tty_port_active(port)) {
1650 uart_flush_buffer(tty);
1651 uart_shutdown(tty, state);
1652 spin_lock_irqsave(&port->lock, flags);
1654 spin_unlock_irqrestore(&port->lock, flags);
1655 tty_port_set_active(port, 0);
1656 tty_port_tty_set(port, NULL);
1657 if (uport && !uart_console(uport))
1658 uart_change_pm(state, UART_PM_STATE_OFF);
1659 wake_up_interruptible(&port->open_wait);
1660 wake_up_interruptible(&port->delta_msr_wait);
1662 mutex_unlock(&port->mutex);
1665 /* uport == NULL if uart_port has already been removed */
1666 static void uart_port_shutdown(struct tty_port *port)
1668 struct uart_state *state = container_of(port, struct uart_state, port);
1669 struct uart_port *uport = uart_port_check(state);
1672 * clear delta_msr_wait queue to avoid mem leaks: we may free
1673 * the irq here so the queue might never be woken up. Note
1674 * that we won't end up waiting on delta_msr_wait again since
1675 * any outstanding file descriptors should be pointing at
1676 * hung_up_tty_fops now.
1678 wake_up_interruptible(&port->delta_msr_wait);
1681 * Free the IRQ and disable the port.
1684 uport->ops->shutdown(uport);
1687 * Ensure that the IRQ handler isn't running on another CPU.
1690 synchronize_irq(uport->irq);
1693 static int uart_carrier_raised(struct tty_port *port)
1695 struct uart_state *state = container_of(port, struct uart_state, port);
1696 struct uart_port *uport;
1699 uport = uart_port_ref(state);
1701 * Should never observe uport == NULL since checks for hangup should
1702 * abort the tty_port_block_til_ready() loop before checking for carrier
1703 * raised -- but report carrier raised if it does anyway so open will
1704 * continue and not sleep
1706 if (WARN_ON(!uport))
1708 spin_lock_irq(&uport->lock);
1709 uart_enable_ms(uport);
1710 mctrl = uport->ops->get_mctrl(uport);
1711 spin_unlock_irq(&uport->lock);
1712 uart_port_deref(uport);
1713 if (mctrl & TIOCM_CAR)
1718 static void uart_dtr_rts(struct tty_port *port, int raise)
1720 struct uart_state *state = container_of(port, struct uart_state, port);
1721 struct uart_port *uport;
1723 uport = uart_port_ref(state);
1726 uart_port_dtr_rts(uport, raise);
1727 uart_port_deref(uport);
1731 * Calls to uart_open are serialised by the tty_lock in
1732 * drivers/tty/tty_io.c:tty_open()
1733 * Note that if this fails, then uart_close() _will_ be called.
1735 * In time, we want to scrap the "opening nonpresent ports"
1736 * behaviour and implement an alternative way for setserial
1737 * to set base addresses/ports/types. This will allow us to
1738 * get rid of a certain amount of extra tests.
1740 static int uart_open(struct tty_struct *tty, struct file *filp)
1742 struct uart_driver *drv = tty->driver->driver_state;
1743 int retval, line = tty->index;
1744 struct uart_state *state = drv->state + line;
1746 tty->driver_data = state;
1748 retval = tty_port_open(&state->port, tty, filp);
1755 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1757 struct uart_state *state = container_of(port, struct uart_state, port);
1758 struct uart_port *uport;
1760 uport = uart_port_check(state);
1761 if (!uport || uport->flags & UPF_DEAD)
1764 port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
1767 * Start up the serial port.
1769 return uart_startup(tty, state, 0);
1772 static const char *uart_type(struct uart_port *port)
1774 const char *str = NULL;
1776 if (port->ops->type)
1777 str = port->ops->type(port);
1785 #ifdef CONFIG_PROC_FS
1787 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1789 struct uart_state *state = drv->state + i;
1790 struct tty_port *port = &state->port;
1791 enum uart_pm_state pm_state;
1792 struct uart_port *uport;
1794 unsigned int status;
1797 mutex_lock(&port->mutex);
1798 uport = uart_port_check(state);
1802 mmio = uport->iotype >= UPIO_MEM;
1803 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
1804 uport->line, uart_type(uport),
1805 mmio ? "mmio:0x" : "port:",
1806 mmio ? (unsigned long long)uport->mapbase
1807 : (unsigned long long)uport->iobase,
1810 if (uport->type == PORT_UNKNOWN) {
1815 if (capable(CAP_SYS_ADMIN)) {
1816 pm_state = state->pm_state;
1817 if (pm_state != UART_PM_STATE_ON)
1818 uart_change_pm(state, UART_PM_STATE_ON);
1819 spin_lock_irq(&uport->lock);
1820 status = uport->ops->get_mctrl(uport);
1821 spin_unlock_irq(&uport->lock);
1822 if (pm_state != UART_PM_STATE_ON)
1823 uart_change_pm(state, pm_state);
1825 seq_printf(m, " tx:%d rx:%d",
1826 uport->icount.tx, uport->icount.rx);
1827 if (uport->icount.frame)
1828 seq_printf(m, " fe:%d", uport->icount.frame);
1829 if (uport->icount.parity)
1830 seq_printf(m, " pe:%d", uport->icount.parity);
1831 if (uport->icount.brk)
1832 seq_printf(m, " brk:%d", uport->icount.brk);
1833 if (uport->icount.overrun)
1834 seq_printf(m, " oe:%d", uport->icount.overrun);
1835 if (uport->icount.buf_overrun)
1836 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
1838 #define INFOBIT(bit, str) \
1839 if (uport->mctrl & (bit)) \
1840 strncat(stat_buf, (str), sizeof(stat_buf) - \
1841 strlen(stat_buf) - 2)
1842 #define STATBIT(bit, str) \
1843 if (status & (bit)) \
1844 strncat(stat_buf, (str), sizeof(stat_buf) - \
1845 strlen(stat_buf) - 2)
1849 INFOBIT(TIOCM_RTS, "|RTS");
1850 STATBIT(TIOCM_CTS, "|CTS");
1851 INFOBIT(TIOCM_DTR, "|DTR");
1852 STATBIT(TIOCM_DSR, "|DSR");
1853 STATBIT(TIOCM_CAR, "|CD");
1854 STATBIT(TIOCM_RNG, "|RI");
1858 seq_puts(m, stat_buf);
1864 mutex_unlock(&port->mutex);
1867 static int uart_proc_show(struct seq_file *m, void *v)
1869 struct tty_driver *ttydrv = m->private;
1870 struct uart_driver *drv = ttydrv->driver_state;
1873 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
1874 for (i = 0; i < drv->nr; i++)
1875 uart_line_info(m, drv, i);
1880 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
1882 * uart_console_write - write a console message to a serial port
1883 * @port: the port to write the message
1884 * @s: array of characters
1885 * @count: number of characters in string to write
1886 * @putchar: function to write character to port
1888 void uart_console_write(struct uart_port *port, const char *s,
1890 void (*putchar)(struct uart_port *, int))
1894 for (i = 0; i < count; i++, s++) {
1896 putchar(port, '\r');
1900 EXPORT_SYMBOL_GPL(uart_console_write);
1903 * Check whether an invalid uart number has been specified, and
1904 * if so, search for the first available port that does have
1907 struct uart_port * __init
1908 uart_get_console(struct uart_port *ports, int nr, struct console *co)
1910 int idx = co->index;
1912 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1913 ports[idx].membase == NULL))
1914 for (idx = 0; idx < nr; idx++)
1915 if (ports[idx].iobase != 0 ||
1916 ports[idx].membase != NULL)
1925 * uart_parse_earlycon - Parse earlycon options
1926 * @p: ptr to 2nd field (ie., just beyond '<name>,')
1927 * @iotype: ptr for decoded iotype (out)
1928 * @addr: ptr for decoded mapbase/iobase (out)
1929 * @options: ptr for <options> field; NULL if not present (out)
1931 * Decodes earlycon kernel command line parameters of the form
1932 * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1933 * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1936 * earlycon=<name>,0x<addr>,<options>
1937 * console=<name>,0x<addr>,<options>
1938 * is also accepted; the returned @iotype will be UPIO_MEM.
1940 * Returns 0 on success or -EINVAL on failure
1942 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
1945 if (strncmp(p, "mmio,", 5) == 0) {
1948 } else if (strncmp(p, "mmio16,", 7) == 0) {
1949 *iotype = UPIO_MEM16;
1951 } else if (strncmp(p, "mmio32,", 7) == 0) {
1952 *iotype = UPIO_MEM32;
1954 } else if (strncmp(p, "mmio32be,", 9) == 0) {
1955 *iotype = UPIO_MEM32BE;
1957 } else if (strncmp(p, "mmio32native,", 13) == 0) {
1958 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
1959 UPIO_MEM32BE : UPIO_MEM32;
1961 } else if (strncmp(p, "io,", 3) == 0) {
1962 *iotype = UPIO_PORT;
1964 } else if (strncmp(p, "0x", 2) == 0) {
1971 * Before you replace it with kstrtoull(), think about options separator
1972 * (',') it will not tolerate
1974 *addr = simple_strtoull(p, NULL, 0);
1982 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
1985 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
1986 * @options: pointer to option string
1987 * @baud: pointer to an 'int' variable for the baud rate.
1988 * @parity: pointer to an 'int' variable for the parity.
1989 * @bits: pointer to an 'int' variable for the number of data bits.
1990 * @flow: pointer to an 'int' variable for the flow control character.
1992 * uart_parse_options decodes a string containing the serial console
1993 * options. The format of the string is <baud><parity><bits><flow>,
1997 uart_parse_options(const char *options, int *baud, int *parity,
1998 int *bits, int *flow)
2000 const char *s = options;
2002 *baud = simple_strtoul(s, NULL, 10);
2003 while (*s >= '0' && *s <= '9')
2012 EXPORT_SYMBOL_GPL(uart_parse_options);
2015 * uart_set_options - setup the serial console parameters
2016 * @port: pointer to the serial ports uart_port structure
2017 * @co: console pointer
2019 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2020 * @bits: number of data bits
2021 * @flow: flow control character - 'r' (rts)
2024 uart_set_options(struct uart_port *port, struct console *co,
2025 int baud, int parity, int bits, int flow)
2027 struct ktermios termios;
2028 static struct ktermios dummy;
2031 * Ensure that the serial console lock is initialised
2033 * If this port is a console, then the spinlock is already
2036 if (!(uart_console(port) && (port->cons->flags & CON_ENABLED))) {
2037 spin_lock_init(&port->lock);
2038 lockdep_set_class(&port->lock, &port_lock_key);
2041 memset(&termios, 0, sizeof(struct ktermios));
2043 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2044 tty_termios_encode_baud_rate(&termios, baud, baud);
2047 termios.c_cflag |= CS7;
2049 termios.c_cflag |= CS8;
2053 termios.c_cflag |= PARODD;
2056 termios.c_cflag |= PARENB;
2061 termios.c_cflag |= CRTSCTS;
2064 * some uarts on other side don't support no flow control.
2065 * So we set * DTR in host uart to make them happy
2067 port->mctrl |= TIOCM_DTR;
2069 port->ops->set_termios(port, &termios, &dummy);
2071 * Allow the setting of the UART parameters with a NULL console
2075 co->cflag = termios.c_cflag;
2079 EXPORT_SYMBOL_GPL(uart_set_options);
2080 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2083 * uart_change_pm - set power state of the port
2085 * @state: port descriptor
2086 * @pm_state: new state
2088 * Locking: port->mutex has to be held
2090 static void uart_change_pm(struct uart_state *state,
2091 enum uart_pm_state pm_state)
2093 struct uart_port *port = uart_port_check(state);
2095 if (state->pm_state != pm_state) {
2096 if (port && port->ops->pm)
2097 port->ops->pm(port, pm_state, state->pm_state);
2098 state->pm_state = pm_state;
2103 struct uart_port *port;
2104 struct uart_driver *driver;
2107 static int serial_match_port(struct device *dev, void *data)
2109 struct uart_match *match = data;
2110 struct tty_driver *tty_drv = match->driver->tty_driver;
2111 dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2114 return dev->devt == devt; /* Actually, only one tty per port */
2117 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2119 struct uart_state *state = drv->state + uport->line;
2120 struct tty_port *port = &state->port;
2121 struct device *tty_dev;
2122 struct uart_match match = {uport, drv};
2124 mutex_lock(&port->mutex);
2126 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2127 if (tty_dev && device_may_wakeup(tty_dev)) {
2128 enable_irq_wake(uport->irq);
2129 put_device(tty_dev);
2130 mutex_unlock(&port->mutex);
2133 put_device(tty_dev);
2135 /* Nothing to do if the console is not suspending */
2136 if (!console_suspend_enabled && uart_console(uport))
2139 uport->suspended = 1;
2141 if (tty_port_initialized(port)) {
2142 const struct uart_ops *ops = uport->ops;
2145 tty_port_set_suspended(port, 1);
2146 tty_port_set_initialized(port, 0);
2148 spin_lock_irq(&uport->lock);
2149 ops->stop_tx(uport);
2150 ops->set_mctrl(uport, 0);
2151 ops->stop_rx(uport);
2152 spin_unlock_irq(&uport->lock);
2155 * Wait for the transmitter to empty.
2157 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2160 dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2163 ops->shutdown(uport);
2167 * Disable the console device before suspending.
2169 if (uart_console(uport))
2170 console_stop(uport->cons);
2172 uart_change_pm(state, UART_PM_STATE_OFF);
2174 mutex_unlock(&port->mutex);
2179 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2181 struct uart_state *state = drv->state + uport->line;
2182 struct tty_port *port = &state->port;
2183 struct device *tty_dev;
2184 struct uart_match match = {uport, drv};
2185 struct ktermios termios;
2187 mutex_lock(&port->mutex);
2189 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2190 if (!uport->suspended && device_may_wakeup(tty_dev)) {
2191 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2192 disable_irq_wake(uport->irq);
2193 put_device(tty_dev);
2194 mutex_unlock(&port->mutex);
2197 put_device(tty_dev);
2198 uport->suspended = 0;
2201 * Re-enable the console device after suspending.
2203 if (uart_console(uport)) {
2205 * First try to use the console cflag setting.
2207 memset(&termios, 0, sizeof(struct ktermios));
2208 termios.c_cflag = uport->cons->cflag;
2211 * If that's unset, use the tty termios setting.
2213 if (port->tty && termios.c_cflag == 0)
2214 termios = port->tty->termios;
2216 if (console_suspend_enabled)
2217 uart_change_pm(state, UART_PM_STATE_ON);
2218 uport->ops->set_termios(uport, &termios, NULL);
2219 if (console_suspend_enabled)
2220 console_start(uport->cons);
2223 if (tty_port_suspended(port)) {
2224 const struct uart_ops *ops = uport->ops;
2227 uart_change_pm(state, UART_PM_STATE_ON);
2228 spin_lock_irq(&uport->lock);
2229 ops->set_mctrl(uport, 0);
2230 spin_unlock_irq(&uport->lock);
2231 if (console_suspend_enabled || !uart_console(uport)) {
2232 /* Protected by port mutex for now */
2233 struct tty_struct *tty = port->tty;
2234 ret = ops->startup(uport);
2237 uart_change_speed(tty, state, NULL);
2238 spin_lock_irq(&uport->lock);
2239 ops->set_mctrl(uport, uport->mctrl);
2240 ops->start_tx(uport);
2241 spin_unlock_irq(&uport->lock);
2242 tty_port_set_initialized(port, 1);
2245 * Failed to resume - maybe hardware went away?
2246 * Clear the "initialized" flag so we won't try
2247 * to call the low level drivers shutdown method.
2249 uart_shutdown(tty, state);
2253 tty_port_set_suspended(port, 0);
2256 mutex_unlock(&port->mutex);
2262 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2266 switch (port->iotype) {
2268 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2271 snprintf(address, sizeof(address),
2272 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2280 snprintf(address, sizeof(address),
2281 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2284 strlcpy(address, "*unknown*", sizeof(address));
2288 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2289 port->dev ? dev_name(port->dev) : "",
2290 port->dev ? ": " : "",
2292 address, port->irq, port->uartclk / 16, uart_type(port));
2296 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2297 struct uart_port *port)
2302 * If there isn't a port here, don't do anything further.
2304 if (!port->iobase && !port->mapbase && !port->membase)
2308 * Now do the auto configuration stuff. Note that config_port
2309 * is expected to claim the resources and map the port for us.
2312 if (port->flags & UPF_AUTO_IRQ)
2313 flags |= UART_CONFIG_IRQ;
2314 if (port->flags & UPF_BOOT_AUTOCONF) {
2315 if (!(port->flags & UPF_FIXED_TYPE)) {
2316 port->type = PORT_UNKNOWN;
2317 flags |= UART_CONFIG_TYPE;
2319 port->ops->config_port(port, flags);
2322 if (port->type != PORT_UNKNOWN) {
2323 unsigned long flags;
2325 uart_report_port(drv, port);
2327 /* Power up port for set_mctrl() */
2328 uart_change_pm(state, UART_PM_STATE_ON);
2331 * Ensure that the modem control lines are de-activated.
2332 * keep the DTR setting that is set in uart_set_options()
2333 * We probably don't need a spinlock around this, but
2335 spin_lock_irqsave(&port->lock, flags);
2336 port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
2337 spin_unlock_irqrestore(&port->lock, flags);
2340 * If this driver supports console, and it hasn't been
2341 * successfully registered yet, try to re-register it.
2342 * It may be that the port was not available.
2344 if (port->cons && !(port->cons->flags & CON_ENABLED))
2345 register_console(port->cons);
2348 * Power down all ports by default, except the
2349 * console if we have one.
2351 if (!uart_console(port))
2352 uart_change_pm(state, UART_PM_STATE_OFF);
2356 #ifdef CONFIG_CONSOLE_POLL
2358 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2360 struct uart_driver *drv = driver->driver_state;
2361 struct uart_state *state = drv->state + line;
2362 struct tty_port *tport;
2363 struct uart_port *port;
2370 tport = &state->port;
2371 mutex_lock(&tport->mutex);
2373 port = uart_port_check(state);
2374 if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2379 if (port->ops->poll_init) {
2381 * We don't set initialized as we only initialized the hw,
2382 * e.g. state->xmit is still uninitialized.
2384 if (!tty_port_initialized(tport))
2385 ret = port->ops->poll_init(port);
2388 if (!ret && options) {
2389 uart_parse_options(options, &baud, &parity, &bits, &flow);
2390 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2393 mutex_unlock(&tport->mutex);
2397 static int uart_poll_get_char(struct tty_driver *driver, int line)
2399 struct uart_driver *drv = driver->driver_state;
2400 struct uart_state *state = drv->state + line;
2401 struct uart_port *port;
2404 port = uart_port_ref(state);
2406 ret = port->ops->poll_get_char(port);
2407 uart_port_deref(port);
2413 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2415 struct uart_driver *drv = driver->driver_state;
2416 struct uart_state *state = drv->state + line;
2417 struct uart_port *port;
2419 port = uart_port_ref(state);
2424 port->ops->poll_put_char(port, '\r');
2425 port->ops->poll_put_char(port, ch);
2426 uart_port_deref(port);
2430 static const struct tty_operations uart_ops = {
2432 .close = uart_close,
2433 .write = uart_write,
2434 .put_char = uart_put_char,
2435 .flush_chars = uart_flush_chars,
2436 .write_room = uart_write_room,
2437 .chars_in_buffer= uart_chars_in_buffer,
2438 .flush_buffer = uart_flush_buffer,
2439 .ioctl = uart_ioctl,
2440 .throttle = uart_throttle,
2441 .unthrottle = uart_unthrottle,
2442 .send_xchar = uart_send_xchar,
2443 .set_termios = uart_set_termios,
2444 .set_ldisc = uart_set_ldisc,
2446 .start = uart_start,
2447 .hangup = uart_hangup,
2448 .break_ctl = uart_break_ctl,
2449 .wait_until_sent= uart_wait_until_sent,
2450 #ifdef CONFIG_PROC_FS
2451 .proc_show = uart_proc_show,
2453 .tiocmget = uart_tiocmget,
2454 .tiocmset = uart_tiocmset,
2455 .set_serial = uart_set_info_user,
2456 .get_serial = uart_get_info_user,
2457 .get_icount = uart_get_icount,
2458 #ifdef CONFIG_CONSOLE_POLL
2459 .poll_init = uart_poll_init,
2460 .poll_get_char = uart_poll_get_char,
2461 .poll_put_char = uart_poll_put_char,
2465 static const struct tty_port_operations uart_port_ops = {
2466 .carrier_raised = uart_carrier_raised,
2467 .dtr_rts = uart_dtr_rts,
2468 .activate = uart_port_activate,
2469 .shutdown = uart_tty_port_shutdown,
2473 * uart_register_driver - register a driver with the uart core layer
2474 * @drv: low level driver structure
2476 * Register a uart driver with the core driver. We in turn register
2477 * with the tty layer, and initialise the core driver per-port state.
2479 * We have a proc file in /proc/tty/driver which is named after the
2482 * drv->port should be NULL, and the per-port structures should be
2483 * registered using uart_add_one_port after this call has succeeded.
2485 int uart_register_driver(struct uart_driver *drv)
2487 struct tty_driver *normal;
2493 * Maybe we should be using a slab cache for this, especially if
2494 * we have a large number of ports to handle.
2496 drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2500 normal = alloc_tty_driver(drv->nr);
2504 drv->tty_driver = normal;
2506 normal->driver_name = drv->driver_name;
2507 normal->name = drv->dev_name;
2508 normal->major = drv->major;
2509 normal->minor_start = drv->minor;
2510 normal->type = TTY_DRIVER_TYPE_SERIAL;
2511 normal->subtype = SERIAL_TYPE_NORMAL;
2512 normal->init_termios = tty_std_termios;
2513 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2514 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2515 normal->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
2516 normal->driver_state = drv;
2517 tty_set_operations(normal, &uart_ops);
2520 * Initialise the UART state(s).
2522 for (i = 0; i < drv->nr; i++) {
2523 struct uart_state *state = drv->state + i;
2524 struct tty_port *port = &state->port;
2526 tty_port_init(port);
2527 port->ops = &uart_port_ops;
2530 retval = tty_register_driver(normal);
2534 for (i = 0; i < drv->nr; i++)
2535 tty_port_destroy(&drv->state[i].port);
2536 put_tty_driver(normal);
2544 * uart_unregister_driver - remove a driver from the uart core layer
2545 * @drv: low level driver structure
2547 * Remove all references to a driver from the core driver. The low
2548 * level driver must have removed all its ports via the
2549 * uart_remove_one_port() if it registered them with uart_add_one_port().
2550 * (ie, drv->port == NULL)
2552 void uart_unregister_driver(struct uart_driver *drv)
2554 struct tty_driver *p = drv->tty_driver;
2557 tty_unregister_driver(p);
2559 for (i = 0; i < drv->nr; i++)
2560 tty_port_destroy(&drv->state[i].port);
2563 drv->tty_driver = NULL;
2566 struct tty_driver *uart_console_device(struct console *co, int *index)
2568 struct uart_driver *p = co->data;
2570 return p->tty_driver;
2573 static ssize_t uart_get_attr_uartclk(struct device *dev,
2574 struct device_attribute *attr, char *buf)
2576 struct serial_struct tmp;
2577 struct tty_port *port = dev_get_drvdata(dev);
2579 uart_get_info(port, &tmp);
2580 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.baud_base * 16);
2583 static ssize_t uart_get_attr_type(struct device *dev,
2584 struct device_attribute *attr, char *buf)
2586 struct serial_struct tmp;
2587 struct tty_port *port = dev_get_drvdata(dev);
2589 uart_get_info(port, &tmp);
2590 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.type);
2592 static ssize_t uart_get_attr_line(struct device *dev,
2593 struct device_attribute *attr, char *buf)
2595 struct serial_struct tmp;
2596 struct tty_port *port = dev_get_drvdata(dev);
2598 uart_get_info(port, &tmp);
2599 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.line);
2602 static ssize_t uart_get_attr_port(struct device *dev,
2603 struct device_attribute *attr, char *buf)
2605 struct serial_struct tmp;
2606 struct tty_port *port = dev_get_drvdata(dev);
2607 unsigned long ioaddr;
2609 uart_get_info(port, &tmp);
2611 if (HIGH_BITS_OFFSET)
2612 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2613 return snprintf(buf, PAGE_SIZE, "0x%lX\n", ioaddr);
2616 static ssize_t uart_get_attr_irq(struct device *dev,
2617 struct device_attribute *attr, char *buf)
2619 struct serial_struct tmp;
2620 struct tty_port *port = dev_get_drvdata(dev);
2622 uart_get_info(port, &tmp);
2623 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.irq);
2626 static ssize_t uart_get_attr_flags(struct device *dev,
2627 struct device_attribute *attr, char *buf)
2629 struct serial_struct tmp;
2630 struct tty_port *port = dev_get_drvdata(dev);
2632 uart_get_info(port, &tmp);
2633 return snprintf(buf, PAGE_SIZE, "0x%X\n", tmp.flags);
2636 static ssize_t uart_get_attr_xmit_fifo_size(struct device *dev,
2637 struct device_attribute *attr, char *buf)
2639 struct serial_struct tmp;
2640 struct tty_port *port = dev_get_drvdata(dev);
2642 uart_get_info(port, &tmp);
2643 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.xmit_fifo_size);
2647 static ssize_t uart_get_attr_close_delay(struct device *dev,
2648 struct device_attribute *attr, char *buf)
2650 struct serial_struct tmp;
2651 struct tty_port *port = dev_get_drvdata(dev);
2653 uart_get_info(port, &tmp);
2654 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.close_delay);
2658 static ssize_t uart_get_attr_closing_wait(struct device *dev,
2659 struct device_attribute *attr, char *buf)
2661 struct serial_struct tmp;
2662 struct tty_port *port = dev_get_drvdata(dev);
2664 uart_get_info(port, &tmp);
2665 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.closing_wait);
2668 static ssize_t uart_get_attr_custom_divisor(struct device *dev,
2669 struct device_attribute *attr, char *buf)
2671 struct serial_struct tmp;
2672 struct tty_port *port = dev_get_drvdata(dev);
2674 uart_get_info(port, &tmp);
2675 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.custom_divisor);
2678 static ssize_t uart_get_attr_io_type(struct device *dev,
2679 struct device_attribute *attr, char *buf)
2681 struct serial_struct tmp;
2682 struct tty_port *port = dev_get_drvdata(dev);
2684 uart_get_info(port, &tmp);
2685 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.io_type);
2688 static ssize_t uart_get_attr_iomem_base(struct device *dev,
2689 struct device_attribute *attr, char *buf)
2691 struct serial_struct tmp;
2692 struct tty_port *port = dev_get_drvdata(dev);
2694 uart_get_info(port, &tmp);
2695 return snprintf(buf, PAGE_SIZE, "0x%lX\n", (unsigned long)tmp.iomem_base);
2698 static ssize_t uart_get_attr_iomem_reg_shift(struct device *dev,
2699 struct device_attribute *attr, char *buf)
2701 struct serial_struct tmp;
2702 struct tty_port *port = dev_get_drvdata(dev);
2704 uart_get_info(port, &tmp);
2705 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.iomem_reg_shift);
2708 static DEVICE_ATTR(type, S_IRUSR | S_IRGRP, uart_get_attr_type, NULL);
2709 static DEVICE_ATTR(line, S_IRUSR | S_IRGRP, uart_get_attr_line, NULL);
2710 static DEVICE_ATTR(port, S_IRUSR | S_IRGRP, uart_get_attr_port, NULL);
2711 static DEVICE_ATTR(irq, S_IRUSR | S_IRGRP, uart_get_attr_irq, NULL);
2712 static DEVICE_ATTR(flags, S_IRUSR | S_IRGRP, uart_get_attr_flags, NULL);
2713 static DEVICE_ATTR(xmit_fifo_size, S_IRUSR | S_IRGRP, uart_get_attr_xmit_fifo_size, NULL);
2714 static DEVICE_ATTR(uartclk, S_IRUSR | S_IRGRP, uart_get_attr_uartclk, NULL);
2715 static DEVICE_ATTR(close_delay, S_IRUSR | S_IRGRP, uart_get_attr_close_delay, NULL);
2716 static DEVICE_ATTR(closing_wait, S_IRUSR | S_IRGRP, uart_get_attr_closing_wait, NULL);
2717 static DEVICE_ATTR(custom_divisor, S_IRUSR | S_IRGRP, uart_get_attr_custom_divisor, NULL);
2718 static DEVICE_ATTR(io_type, S_IRUSR | S_IRGRP, uart_get_attr_io_type, NULL);
2719 static DEVICE_ATTR(iomem_base, S_IRUSR | S_IRGRP, uart_get_attr_iomem_base, NULL);
2720 static DEVICE_ATTR(iomem_reg_shift, S_IRUSR | S_IRGRP, uart_get_attr_iomem_reg_shift, NULL);
2722 static struct attribute *tty_dev_attrs[] = {
2723 &dev_attr_type.attr,
2724 &dev_attr_line.attr,
2725 &dev_attr_port.attr,
2727 &dev_attr_flags.attr,
2728 &dev_attr_xmit_fifo_size.attr,
2729 &dev_attr_uartclk.attr,
2730 &dev_attr_close_delay.attr,
2731 &dev_attr_closing_wait.attr,
2732 &dev_attr_custom_divisor.attr,
2733 &dev_attr_io_type.attr,
2734 &dev_attr_iomem_base.attr,
2735 &dev_attr_iomem_reg_shift.attr,
2739 static const struct attribute_group tty_dev_attr_group = {
2740 .attrs = tty_dev_attrs,
2744 * uart_add_one_port - attach a driver-defined port structure
2745 * @drv: pointer to the uart low level driver structure for this port
2746 * @uport: uart port structure to use for this port.
2748 * This allows the driver to register its own uart_port structure
2749 * with the core driver. The main purpose is to allow the low
2750 * level uart drivers to expand uart_port, rather than having yet
2751 * more levels of structures.
2753 int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
2755 struct uart_state *state;
2756 struct tty_port *port;
2758 struct device *tty_dev;
2761 BUG_ON(in_interrupt());
2763 if (uport->line >= drv->nr)
2766 state = drv->state + uport->line;
2767 port = &state->port;
2769 mutex_lock(&port_mutex);
2770 mutex_lock(&port->mutex);
2771 if (state->uart_port) {
2776 /* Link the port to the driver state table and vice versa */
2777 atomic_set(&state->refcount, 1);
2778 init_waitqueue_head(&state->remove_wait);
2779 state->uart_port = uport;
2780 uport->state = state;
2782 state->pm_state = UART_PM_STATE_UNDEFINED;
2783 uport->cons = drv->cons;
2784 uport->minor = drv->tty_driver->minor_start + uport->line;
2785 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
2786 drv->tty_driver->name_base + uport->line);
2793 * If this port is a console, then the spinlock is already
2796 if (!(uart_console(uport) && (uport->cons->flags & CON_ENABLED))) {
2797 spin_lock_init(&uport->lock);
2798 lockdep_set_class(&uport->lock, &port_lock_key);
2800 if (uport->cons && uport->dev)
2801 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
2803 uart_configure_port(drv, state, uport);
2805 port->console = uart_console(uport);
2808 if (uport->attr_group)
2811 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
2813 if (!uport->tty_groups) {
2817 uport->tty_groups[0] = &tty_dev_attr_group;
2818 if (uport->attr_group)
2819 uport->tty_groups[1] = uport->attr_group;
2822 * Register the port whether it's detected or not. This allows
2823 * setserial to be used to alter this port's parameters.
2825 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
2826 uport->line, uport->dev, port, uport->tty_groups);
2827 if (likely(!IS_ERR(tty_dev))) {
2828 device_set_wakeup_capable(tty_dev, 1);
2830 dev_err(uport->dev, "Cannot register tty device on line %d\n",
2835 * Ensure UPF_DEAD is not set.
2837 uport->flags &= ~UPF_DEAD;
2840 mutex_unlock(&port->mutex);
2841 mutex_unlock(&port_mutex);
2847 * uart_remove_one_port - detach a driver defined port structure
2848 * @drv: pointer to the uart low level driver structure for this port
2849 * @uport: uart port structure for this port
2851 * This unhooks (and hangs up) the specified port structure from the
2852 * core driver. No further calls will be made to the low-level code
2855 int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
2857 struct uart_state *state = drv->state + uport->line;
2858 struct tty_port *port = &state->port;
2859 struct uart_port *uart_port;
2860 struct tty_struct *tty;
2863 BUG_ON(in_interrupt());
2865 mutex_lock(&port_mutex);
2868 * Mark the port "dead" - this prevents any opens from
2869 * succeeding while we shut down the port.
2871 mutex_lock(&port->mutex);
2872 uart_port = uart_port_check(state);
2873 if (uart_port != uport)
2874 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
2878 mutex_unlock(&port->mutex);
2882 uport->flags |= UPF_DEAD;
2883 mutex_unlock(&port->mutex);
2886 * Remove the devices from the tty layer
2888 tty_port_unregister_device(port, drv->tty_driver, uport->line);
2890 tty = tty_port_tty_get(port);
2892 tty_vhangup(port->tty);
2897 * If the port is used as a console, unregister it
2899 if (uart_console(uport))
2900 unregister_console(uport->cons);
2903 * Free the port IO and memory resources, if any.
2905 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
2906 uport->ops->release_port(uport);
2907 kfree(uport->tty_groups);
2911 * Indicate that there isn't a port here anymore.
2913 uport->type = PORT_UNKNOWN;
2915 mutex_lock(&port->mutex);
2916 WARN_ON(atomic_dec_return(&state->refcount) < 0);
2917 wait_event(state->remove_wait, !atomic_read(&state->refcount));
2918 state->uart_port = NULL;
2919 mutex_unlock(&port->mutex);
2921 mutex_unlock(&port_mutex);
2927 * Are the two ports equivalent?
2929 int uart_match_port(struct uart_port *port1, struct uart_port *port2)
2931 if (port1->iotype != port2->iotype)
2934 switch (port1->iotype) {
2936 return (port1->iobase == port2->iobase);
2938 return (port1->iobase == port2->iobase) &&
2939 (port1->hub6 == port2->hub6);
2946 return (port1->mapbase == port2->mapbase);
2950 EXPORT_SYMBOL(uart_match_port);
2953 * uart_handle_dcd_change - handle a change of carrier detect state
2954 * @uport: uart_port structure for the open port
2955 * @status: new carrier detect status, nonzero if active
2957 * Caller must hold uport->lock
2959 void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
2961 struct tty_port *port = &uport->state->port;
2962 struct tty_struct *tty = port->tty;
2963 struct tty_ldisc *ld;
2965 lockdep_assert_held_once(&uport->lock);
2968 ld = tty_ldisc_ref(tty);
2970 if (ld->ops->dcd_change)
2971 ld->ops->dcd_change(tty, status);
2972 tty_ldisc_deref(ld);
2976 uport->icount.dcd++;
2978 if (uart_dcd_enabled(uport)) {
2980 wake_up_interruptible(&port->open_wait);
2985 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
2988 * uart_handle_cts_change - handle a change of clear-to-send state
2989 * @uport: uart_port structure for the open port
2990 * @status: new clear to send status, nonzero if active
2992 * Caller must hold uport->lock
2994 void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
2996 lockdep_assert_held_once(&uport->lock);
2998 uport->icount.cts++;
3000 if (uart_softcts_mode(uport)) {
3001 if (uport->hw_stopped) {
3003 uport->hw_stopped = 0;
3004 uport->ops->start_tx(uport);
3005 uart_write_wakeup(uport);
3009 uport->hw_stopped = 1;
3010 uport->ops->stop_tx(uport);
3016 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3019 * uart_insert_char - push a char to the uart layer
3021 * User is responsible to call tty_flip_buffer_push when they are done with
3024 * @port: corresponding port
3025 * @status: state of the serial port RX buffer (LSR for 8250)
3026 * @overrun: mask of overrun bits in @status
3027 * @ch: character to push
3028 * @flag: flag for the character (see TTY_NORMAL and friends)
3030 void uart_insert_char(struct uart_port *port, unsigned int status,
3031 unsigned int overrun, unsigned int ch, unsigned int flag)
3033 struct tty_port *tport = &port->state->port;
3035 if ((status & port->ignore_status_mask & ~overrun) == 0)
3036 if (tty_insert_flip_char(tport, ch, flag) == 0)
3037 ++port->icount.buf_overrun;
3040 * Overrun is special. Since it's reported immediately,
3041 * it doesn't affect the current character.
3043 if (status & ~port->ignore_status_mask & overrun)
3044 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3045 ++port->icount.buf_overrun;
3047 EXPORT_SYMBOL_GPL(uart_insert_char);
3049 EXPORT_SYMBOL(uart_write_wakeup);
3050 EXPORT_SYMBOL(uart_register_driver);
3051 EXPORT_SYMBOL(uart_unregister_driver);
3052 EXPORT_SYMBOL(uart_suspend_port);
3053 EXPORT_SYMBOL(uart_resume_port);
3054 EXPORT_SYMBOL(uart_add_one_port);
3055 EXPORT_SYMBOL(uart_remove_one_port);
3058 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3060 * @rs485conf: output parameter
3062 * This function implements the device tree binding described in
3063 * Documentation/devicetree/bindings/serial/rs485.txt.
3065 void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf)
3070 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3073 rs485conf->delay_rts_before_send = rs485_delay[0];
3074 rs485conf->delay_rts_after_send = rs485_delay[1];
3076 rs485conf->delay_rts_before_send = 0;
3077 rs485conf->delay_rts_after_send = 0;
3081 * Clear full-duplex and enabled flags, set RTS polarity to active high
3082 * to get to a defined state with the following properties:
3084 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3085 SER_RS485_RTS_AFTER_SEND);
3086 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3088 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3089 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3091 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3092 rs485conf->flags |= SER_RS485_ENABLED;
3094 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3095 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3096 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3099 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3101 MODULE_DESCRIPTION("Serial driver core");
3102 MODULE_LICENSE("GPL");