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/math64.h>
28 #include <linux/security.h>
30 #include <linux/irq.h>
31 #include <linux/uaccess.h>
34 * This is used to lock changes in serial line configuration.
36 static DEFINE_MUTEX(port_mutex);
39 * lockdep: port->lock is initialized in two places, but we
40 * want only one lock-class:
42 static struct lock_class_key port_lock_key;
44 #define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
47 * Max time with active RTS before/after data is sent.
49 #define RS485_MAX_RTS_DELAY 100 /* msecs */
51 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
52 struct ktermios *old_termios);
53 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
54 static void uart_change_pm(struct uart_state *state,
55 enum uart_pm_state pm_state);
57 static void uart_port_shutdown(struct tty_port *port);
59 static int uart_dcd_enabled(struct uart_port *uport)
61 return !!(uport->status & UPSTAT_DCD_ENABLE);
64 static inline struct uart_port *uart_port_ref(struct uart_state *state)
66 if (atomic_add_unless(&state->refcount, 1, 0))
67 return state->uart_port;
71 static inline void uart_port_deref(struct uart_port *uport)
73 if (atomic_dec_and_test(&uport->state->refcount))
74 wake_up(&uport->state->remove_wait);
77 #define uart_port_lock(state, flags) \
79 struct uart_port *__uport = uart_port_ref(state); \
81 spin_lock_irqsave(&__uport->lock, flags); \
85 #define uart_port_unlock(uport, flags) \
87 struct uart_port *__uport = uport; \
89 spin_unlock_irqrestore(&__uport->lock, flags); \
90 uart_port_deref(__uport); \
94 static inline struct uart_port *uart_port_check(struct uart_state *state)
96 lockdep_assert_held(&state->port.mutex);
97 return state->uart_port;
101 * This routine is used by the interrupt handler to schedule processing in
102 * the software interrupt portion of the driver.
104 void uart_write_wakeup(struct uart_port *port)
106 struct uart_state *state = port->state;
108 * This means you called this function _after_ the port was
109 * closed. No cookie for you.
112 tty_port_tty_wakeup(&state->port);
114 EXPORT_SYMBOL(uart_write_wakeup);
116 static void uart_stop(struct tty_struct *tty)
118 struct uart_state *state = tty->driver_data;
119 struct uart_port *port;
122 port = uart_port_lock(state, flags);
124 port->ops->stop_tx(port);
125 uart_port_unlock(port, flags);
128 static void __uart_start(struct tty_struct *tty)
130 struct uart_state *state = tty->driver_data;
131 struct uart_port *port = state->uart_port;
133 if (port && !uart_tx_stopped(port))
134 port->ops->start_tx(port);
137 static void uart_start(struct tty_struct *tty)
139 struct uart_state *state = tty->driver_data;
140 struct uart_port *port;
143 port = uart_port_lock(state, flags);
145 uart_port_unlock(port, flags);
149 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
154 if (port->rs485.flags & SER_RS485_ENABLED) {
159 spin_lock_irqsave(&port->lock, flags);
161 port->mctrl = (old & ~clear) | set;
162 if (old != port->mctrl)
163 port->ops->set_mctrl(port, port->mctrl);
164 spin_unlock_irqrestore(&port->lock, flags);
167 #define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
168 #define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
170 static void uart_port_dtr_rts(struct uart_port *uport, int raise)
173 uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
175 uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
179 * Startup the port. This will be called once per open. All calls
180 * will be serialised by the per-port mutex.
182 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
185 struct uart_port *uport = uart_port_check(state);
190 if (uport->type == PORT_UNKNOWN)
194 * Make sure the device is in D0 state.
196 uart_change_pm(state, UART_PM_STATE_ON);
199 * Initialise and allocate the transmit and temporary
202 page = get_zeroed_page(GFP_KERNEL);
206 uart_port_lock(state, flags);
207 if (!state->xmit.buf) {
208 state->xmit.buf = (unsigned char *) page;
209 uart_circ_clear(&state->xmit);
210 uart_port_unlock(uport, flags);
212 uart_port_unlock(uport, flags);
214 * Do not free() the page under the port lock, see
220 retval = uport->ops->startup(uport);
222 if (uart_console(uport) && uport->cons->cflag) {
223 tty->termios.c_cflag = uport->cons->cflag;
224 tty->termios.c_ispeed = uport->cons->ispeed;
225 tty->termios.c_ospeed = uport->cons->ospeed;
226 uport->cons->cflag = 0;
227 uport->cons->ispeed = 0;
228 uport->cons->ospeed = 0;
231 * Initialise the hardware port settings.
233 uart_change_speed(tty, state, NULL);
236 * Setup the RTS and DTR signals once the
237 * port is open and ready to respond.
239 if (init_hw && C_BAUD(tty))
240 uart_port_dtr_rts(uport, 1);
244 * This is to allow setserial on this port. People may want to set
245 * port/irq/type and then reconfigure the port properly if it failed
248 if (retval && capable(CAP_SYS_ADMIN))
254 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
257 struct tty_port *port = &state->port;
260 if (tty_port_initialized(port))
263 retval = uart_port_startup(tty, state, init_hw);
265 set_bit(TTY_IO_ERROR, &tty->flags);
271 * This routine will shutdown a serial port; interrupts are disabled, and
272 * DTR is dropped if the hangup on close termio flag is on. Calls to
273 * uart_shutdown are serialised by the per-port semaphore.
275 * uport == NULL if uart_port has already been removed
277 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
279 struct uart_port *uport = uart_port_check(state);
280 struct tty_port *port = &state->port;
282 char *xmit_buf = NULL;
285 * Set the TTY IO error marker
288 set_bit(TTY_IO_ERROR, &tty->flags);
290 if (tty_port_initialized(port)) {
291 tty_port_set_initialized(port, 0);
294 * Turn off DTR and RTS early.
296 if (uport && uart_console(uport) && tty) {
297 uport->cons->cflag = tty->termios.c_cflag;
298 uport->cons->ispeed = tty->termios.c_ispeed;
299 uport->cons->ospeed = tty->termios.c_ospeed;
302 if (!tty || C_HUPCL(tty))
303 uart_port_dtr_rts(uport, 0);
305 uart_port_shutdown(port);
309 * It's possible for shutdown to be called after suspend if we get
310 * a DCD drop (hangup) at just the right time. Clear suspended bit so
311 * we don't try to resume a port that has been shutdown.
313 tty_port_set_suspended(port, 0);
316 * Do not free() the transmit buffer page under the port lock since
317 * this can create various circular locking scenarios. For instance,
318 * console driver may need to allocate/free a debug object, which
319 * can endup in printk() recursion.
321 uart_port_lock(state, flags);
322 xmit_buf = state->xmit.buf;
323 state->xmit.buf = NULL;
324 uart_port_unlock(uport, flags);
326 free_page((unsigned long)xmit_buf);
330 * uart_update_timeout - update per-port FIFO timeout.
331 * @port: uart_port structure describing the port
332 * @cflag: termios cflag value
333 * @baud: speed of the port
335 * Set the port FIFO timeout value. The @cflag value should
336 * reflect the actual hardware settings.
339 uart_update_timeout(struct uart_port *port, unsigned int cflag,
342 unsigned int size = tty_get_frame_size(cflag);
345 frame_time = (u64)size * NSEC_PER_SEC;
346 size *= port->fifosize;
349 * Figure the timeout to send the above number of bits.
350 * Add .02 seconds of slop
352 port->timeout = (HZ * size) / baud + HZ/50;
353 port->frame_time = DIV64_U64_ROUND_UP(frame_time, baud);
355 EXPORT_SYMBOL(uart_update_timeout);
358 * uart_get_baud_rate - return baud rate for a particular port
359 * @port: uart_port structure describing the port in question.
360 * @termios: desired termios settings.
361 * @old: old termios (or NULL)
362 * @min: minimum acceptable baud rate
363 * @max: maximum acceptable baud rate
365 * Decode the termios structure into a numeric baud rate,
366 * taking account of the magic 38400 baud rate (with spd_*
367 * flags), and mapping the %B0 rate to 9600 baud.
369 * If the new baud rate is invalid, try the old termios setting.
370 * If it's still invalid, we try 9600 baud.
372 * Update the @termios structure to reflect the baud rate
373 * we're actually going to be using. Don't do this for the case
374 * where B0 is requested ("hang up").
377 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
378 struct ktermios *old, unsigned int min, unsigned int max)
382 unsigned int altbaud;
384 upf_t flags = port->flags & UPF_SPD_MASK;
404 for (try = 0; try < 2; try++) {
405 baud = tty_termios_baud_rate(termios);
408 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
411 if (try == 0 && baud == 38400)
415 * Special case: B0 rate.
422 if (baud >= min && baud <= max)
426 * Oops, the quotient was zero. Try again with
427 * the old baud rate if possible.
429 termios->c_cflag &= ~CBAUD;
431 baud = tty_termios_baud_rate(old);
433 tty_termios_encode_baud_rate(termios,
440 * As a last resort, if the range cannot be met then clip to
441 * the nearest chip supported rate.
445 tty_termios_encode_baud_rate(termios,
448 tty_termios_encode_baud_rate(termios,
452 /* Should never happen */
456 EXPORT_SYMBOL(uart_get_baud_rate);
459 * uart_get_divisor - return uart clock divisor
460 * @port: uart_port structure describing the port.
461 * @baud: desired baud rate
463 * Calculate the uart clock divisor for the port.
466 uart_get_divisor(struct uart_port *port, unsigned int baud)
471 * Old custom speed handling.
473 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
474 quot = port->custom_divisor;
476 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
480 EXPORT_SYMBOL(uart_get_divisor);
482 /* Caller holds port mutex */
483 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
484 struct ktermios *old_termios)
486 struct uart_port *uport = uart_port_check(state);
487 struct ktermios *termios;
491 * If we have no tty, termios, or the port does not exist,
492 * then we can't set the parameters for this port.
494 if (!tty || uport->type == PORT_UNKNOWN)
497 termios = &tty->termios;
498 uport->ops->set_termios(uport, termios, old_termios);
501 * Set modem status enables based on termios cflag
503 spin_lock_irq(&uport->lock);
504 if (termios->c_cflag & CRTSCTS)
505 uport->status |= UPSTAT_CTS_ENABLE;
507 uport->status &= ~UPSTAT_CTS_ENABLE;
509 if (termios->c_cflag & CLOCAL)
510 uport->status &= ~UPSTAT_DCD_ENABLE;
512 uport->status |= UPSTAT_DCD_ENABLE;
514 /* reset sw-assisted CTS flow control based on (possibly) new mode */
515 hw_stopped = uport->hw_stopped;
516 uport->hw_stopped = uart_softcts_mode(uport) &&
517 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
518 if (uport->hw_stopped) {
520 uport->ops->stop_tx(uport);
525 spin_unlock_irq(&uport->lock);
528 static int uart_put_char(struct tty_struct *tty, unsigned char c)
530 struct uart_state *state = tty->driver_data;
531 struct uart_port *port;
532 struct circ_buf *circ;
537 port = uart_port_lock(state, flags);
539 uart_port_unlock(port, flags);
543 if (port && uart_circ_chars_free(circ) != 0) {
544 circ->buf[circ->head] = c;
545 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
548 uart_port_unlock(port, flags);
552 static void uart_flush_chars(struct tty_struct *tty)
557 static int uart_write(struct tty_struct *tty,
558 const unsigned char *buf, int count)
560 struct uart_state *state = tty->driver_data;
561 struct uart_port *port;
562 struct circ_buf *circ;
567 * This means you called this function _after_ the port was
568 * closed. No cookie for you.
575 port = uart_port_lock(state, flags);
578 uart_port_unlock(port, flags);
583 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
588 memcpy(circ->buf + circ->head, buf, c);
589 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
596 uart_port_unlock(port, flags);
600 static unsigned int uart_write_room(struct tty_struct *tty)
602 struct uart_state *state = tty->driver_data;
603 struct uart_port *port;
607 port = uart_port_lock(state, flags);
608 ret = uart_circ_chars_free(&state->xmit);
609 uart_port_unlock(port, flags);
613 static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
615 struct uart_state *state = tty->driver_data;
616 struct uart_port *port;
620 port = uart_port_lock(state, flags);
621 ret = uart_circ_chars_pending(&state->xmit);
622 uart_port_unlock(port, flags);
626 static void uart_flush_buffer(struct tty_struct *tty)
628 struct uart_state *state = tty->driver_data;
629 struct uart_port *port;
633 * This means you called this function _after_ the port was
634 * closed. No cookie for you.
641 pr_debug("uart_flush_buffer(%d) called\n", tty->index);
643 port = uart_port_lock(state, flags);
646 uart_circ_clear(&state->xmit);
647 if (port->ops->flush_buffer)
648 port->ops->flush_buffer(port);
649 uart_port_unlock(port, flags);
650 tty_port_tty_wakeup(&state->port);
654 * This function performs low-level write of high-priority XON/XOFF
655 * character and accounting for it.
657 * Requires uart_port to implement .serial_out().
659 void uart_xchar_out(struct uart_port *uport, int offset)
661 serial_port_out(uport, offset, uport->x_char);
665 EXPORT_SYMBOL_GPL(uart_xchar_out);
668 * This function is used to send a high-priority XON/XOFF character to
671 static void uart_send_xchar(struct tty_struct *tty, char ch)
673 struct uart_state *state = tty->driver_data;
674 struct uart_port *port;
677 port = uart_port_ref(state);
681 if (port->ops->send_xchar)
682 port->ops->send_xchar(port, ch);
684 spin_lock_irqsave(&port->lock, flags);
687 port->ops->start_tx(port);
688 spin_unlock_irqrestore(&port->lock, flags);
690 uart_port_deref(port);
693 static void uart_throttle(struct tty_struct *tty)
695 struct uart_state *state = tty->driver_data;
696 upstat_t mask = UPSTAT_SYNC_FIFO;
697 struct uart_port *port;
699 port = uart_port_ref(state);
704 mask |= UPSTAT_AUTOXOFF;
706 mask |= UPSTAT_AUTORTS;
708 if (port->status & mask) {
709 port->ops->throttle(port);
710 mask &= ~port->status;
713 if (mask & UPSTAT_AUTORTS)
714 uart_clear_mctrl(port, TIOCM_RTS);
716 if (mask & UPSTAT_AUTOXOFF)
717 uart_send_xchar(tty, STOP_CHAR(tty));
719 uart_port_deref(port);
722 static void uart_unthrottle(struct tty_struct *tty)
724 struct uart_state *state = tty->driver_data;
725 upstat_t mask = UPSTAT_SYNC_FIFO;
726 struct uart_port *port;
728 port = uart_port_ref(state);
733 mask |= UPSTAT_AUTOXOFF;
735 mask |= UPSTAT_AUTORTS;
737 if (port->status & mask) {
738 port->ops->unthrottle(port);
739 mask &= ~port->status;
742 if (mask & UPSTAT_AUTORTS)
743 uart_set_mctrl(port, TIOCM_RTS);
745 if (mask & UPSTAT_AUTOXOFF)
746 uart_send_xchar(tty, START_CHAR(tty));
748 uart_port_deref(port);
751 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
753 struct uart_state *state = container_of(port, struct uart_state, port);
754 struct uart_port *uport;
758 * Ensure the state we copy is consistent and no hardware changes
761 mutex_lock(&port->mutex);
762 uport = uart_port_check(state);
766 retinfo->type = uport->type;
767 retinfo->line = uport->line;
768 retinfo->port = uport->iobase;
769 if (HIGH_BITS_OFFSET)
770 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
771 retinfo->irq = uport->irq;
772 retinfo->flags = (__force int)uport->flags;
773 retinfo->xmit_fifo_size = uport->fifosize;
774 retinfo->baud_base = uport->uartclk / 16;
775 retinfo->close_delay = jiffies_to_msecs(port->close_delay) / 10;
776 retinfo->closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
777 ASYNC_CLOSING_WAIT_NONE :
778 jiffies_to_msecs(port->closing_wait) / 10;
779 retinfo->custom_divisor = uport->custom_divisor;
780 retinfo->hub6 = uport->hub6;
781 retinfo->io_type = uport->iotype;
782 retinfo->iomem_reg_shift = uport->regshift;
783 retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
787 mutex_unlock(&port->mutex);
791 static int uart_get_info_user(struct tty_struct *tty,
792 struct serial_struct *ss)
794 struct uart_state *state = tty->driver_data;
795 struct tty_port *port = &state->port;
797 return uart_get_info(port, ss) < 0 ? -EIO : 0;
800 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
801 struct uart_state *state,
802 struct serial_struct *new_info)
804 struct uart_port *uport = uart_port_check(state);
805 unsigned long new_port;
806 unsigned int change_irq, change_port, closing_wait;
807 unsigned int old_custom_divisor, close_delay;
808 upf_t old_flags, new_flags;
814 new_port = new_info->port;
815 if (HIGH_BITS_OFFSET)
816 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
818 new_info->irq = irq_canonicalize(new_info->irq);
819 close_delay = msecs_to_jiffies(new_info->close_delay * 10);
820 closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
821 ASYNC_CLOSING_WAIT_NONE :
822 msecs_to_jiffies(new_info->closing_wait * 10);
825 change_irq = !(uport->flags & UPF_FIXED_PORT)
826 && new_info->irq != uport->irq;
829 * Since changing the 'type' of the port changes its resource
830 * allocations, we should treat type changes the same as
833 change_port = !(uport->flags & UPF_FIXED_PORT)
834 && (new_port != uport->iobase ||
835 (unsigned long)new_info->iomem_base != uport->mapbase ||
836 new_info->hub6 != uport->hub6 ||
837 new_info->io_type != uport->iotype ||
838 new_info->iomem_reg_shift != uport->regshift ||
839 new_info->type != uport->type);
841 old_flags = uport->flags;
842 new_flags = (__force upf_t)new_info->flags;
843 old_custom_divisor = uport->custom_divisor;
845 if (!capable(CAP_SYS_ADMIN)) {
847 if (change_irq || change_port ||
848 (new_info->baud_base != uport->uartclk / 16) ||
849 (close_delay != port->close_delay) ||
850 (closing_wait != port->closing_wait) ||
851 (new_info->xmit_fifo_size &&
852 new_info->xmit_fifo_size != uport->fifosize) ||
853 (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
855 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
856 (new_flags & UPF_USR_MASK));
857 uport->custom_divisor = new_info->custom_divisor;
861 if (change_irq || change_port) {
862 retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
868 * Ask the low level driver to verify the settings.
870 if (uport->ops->verify_port)
871 retval = uport->ops->verify_port(uport, new_info);
873 if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
874 (new_info->baud_base < 9600))
880 if (change_port || change_irq) {
884 * Make sure that we are the sole user of this port.
886 if (tty_port_users(port) > 1)
890 * We need to shutdown the serial port at the old
891 * port/type/irq combination.
893 uart_shutdown(tty, state);
897 unsigned long old_iobase, old_mapbase;
898 unsigned int old_type, old_iotype, old_hub6, old_shift;
900 old_iobase = uport->iobase;
901 old_mapbase = uport->mapbase;
902 old_type = uport->type;
903 old_hub6 = uport->hub6;
904 old_iotype = uport->iotype;
905 old_shift = uport->regshift;
908 * Free and release old regions
910 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
911 uport->ops->release_port(uport);
913 uport->iobase = new_port;
914 uport->type = new_info->type;
915 uport->hub6 = new_info->hub6;
916 uport->iotype = new_info->io_type;
917 uport->regshift = new_info->iomem_reg_shift;
918 uport->mapbase = (unsigned long)new_info->iomem_base;
921 * Claim and map the new regions
923 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
924 retval = uport->ops->request_port(uport);
926 /* Always success - Jean II */
931 * If we fail to request resources for the
932 * new port, try to restore the old settings.
935 uport->iobase = old_iobase;
936 uport->type = old_type;
937 uport->hub6 = old_hub6;
938 uport->iotype = old_iotype;
939 uport->regshift = old_shift;
940 uport->mapbase = old_mapbase;
942 if (old_type != PORT_UNKNOWN) {
943 retval = uport->ops->request_port(uport);
945 * If we failed to restore the old settings,
949 uport->type = PORT_UNKNOWN;
957 /* Added to return the correct error -Ram Gupta */
963 uport->irq = new_info->irq;
964 if (!(uport->flags & UPF_FIXED_PORT))
965 uport->uartclk = new_info->baud_base * 16;
966 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
967 (new_flags & UPF_CHANGE_MASK);
968 uport->custom_divisor = new_info->custom_divisor;
969 port->close_delay = close_delay;
970 port->closing_wait = closing_wait;
971 if (new_info->xmit_fifo_size)
972 uport->fifosize = new_info->xmit_fifo_size;
976 if (uport->type == PORT_UNKNOWN)
978 if (tty_port_initialized(port)) {
979 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
980 old_custom_divisor != uport->custom_divisor) {
982 * If they're setting up a custom divisor or speed,
983 * instead of clearing it, then bitch about it.
985 if (uport->flags & UPF_SPD_MASK) {
986 dev_notice_ratelimited(uport->dev,
987 "%s sets custom speed on %s. This is deprecated.\n",
989 tty_name(port->tty));
991 uart_change_speed(tty, state, NULL);
994 retval = uart_startup(tty, state, 1);
996 tty_port_set_initialized(port, true);
1004 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1006 struct uart_state *state = tty->driver_data;
1007 struct tty_port *port = &state->port;
1010 down_write(&tty->termios_rwsem);
1012 * This semaphore protects port->count. It is also
1013 * very useful to prevent opens. Also, take the
1014 * port configuration semaphore to make sure that a
1015 * module insertion/removal doesn't change anything
1018 mutex_lock(&port->mutex);
1019 retval = uart_set_info(tty, port, state, ss);
1020 mutex_unlock(&port->mutex);
1021 up_write(&tty->termios_rwsem);
1026 * uart_get_lsr_info - get line status register info
1027 * @tty: tty associated with the UART
1028 * @state: UART being queried
1029 * @value: returned modem value
1031 static int uart_get_lsr_info(struct tty_struct *tty,
1032 struct uart_state *state, unsigned int __user *value)
1034 struct uart_port *uport = uart_port_check(state);
1035 unsigned int result;
1037 result = uport->ops->tx_empty(uport);
1040 * If we're about to load something into the transmit
1041 * register, we'll pretend the transmitter isn't empty to
1042 * avoid a race condition (depending on when the transmit
1043 * interrupt happens).
1045 if (uport->x_char ||
1046 ((uart_circ_chars_pending(&state->xmit) > 0) &&
1047 !uart_tx_stopped(uport)))
1048 result &= ~TIOCSER_TEMT;
1050 return put_user(result, value);
1053 static int uart_tiocmget(struct tty_struct *tty)
1055 struct uart_state *state = tty->driver_data;
1056 struct tty_port *port = &state->port;
1057 struct uart_port *uport;
1060 mutex_lock(&port->mutex);
1061 uport = uart_port_check(state);
1065 if (!tty_io_error(tty)) {
1066 result = uport->mctrl;
1067 spin_lock_irq(&uport->lock);
1068 result |= uport->ops->get_mctrl(uport);
1069 spin_unlock_irq(&uport->lock);
1072 mutex_unlock(&port->mutex);
1077 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1079 struct uart_state *state = tty->driver_data;
1080 struct tty_port *port = &state->port;
1081 struct uart_port *uport;
1084 mutex_lock(&port->mutex);
1085 uport = uart_port_check(state);
1089 if (!tty_io_error(tty)) {
1090 uart_update_mctrl(uport, set, clear);
1094 mutex_unlock(&port->mutex);
1098 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1100 struct uart_state *state = tty->driver_data;
1101 struct tty_port *port = &state->port;
1102 struct uart_port *uport;
1105 mutex_lock(&port->mutex);
1106 uport = uart_port_check(state);
1110 if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1111 uport->ops->break_ctl(uport, break_state);
1114 mutex_unlock(&port->mutex);
1118 static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1120 struct tty_port *port = &state->port;
1121 struct uart_port *uport;
1124 if (!capable(CAP_SYS_ADMIN))
1128 * Take the per-port semaphore. This prevents count from
1129 * changing, and hence any extra opens of the port while
1130 * we're auto-configuring.
1132 if (mutex_lock_interruptible(&port->mutex))
1133 return -ERESTARTSYS;
1135 uport = uart_port_check(state);
1142 if (tty_port_users(port) == 1) {
1143 uart_shutdown(tty, state);
1146 * If we already have a port type configured,
1147 * we must release its resources.
1149 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1150 uport->ops->release_port(uport);
1152 flags = UART_CONFIG_TYPE;
1153 if (uport->flags & UPF_AUTO_IRQ)
1154 flags |= UART_CONFIG_IRQ;
1157 * This will claim the ports resources if
1160 uport->ops->config_port(uport, flags);
1162 ret = uart_startup(tty, state, 1);
1164 tty_port_set_initialized(port, true);
1169 mutex_unlock(&port->mutex);
1173 static void uart_enable_ms(struct uart_port *uport)
1176 * Force modem status interrupts on
1178 if (uport->ops->enable_ms)
1179 uport->ops->enable_ms(uport);
1183 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1184 * - mask passed in arg for lines of interest
1185 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1186 * Caller should use TIOCGICOUNT to see which one it was
1188 * FIXME: This wants extracting into a common all driver implementation
1189 * of TIOCMWAIT using tty_port.
1191 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1193 struct uart_port *uport;
1194 struct tty_port *port = &state->port;
1195 DECLARE_WAITQUEUE(wait, current);
1196 struct uart_icount cprev, cnow;
1200 * note the counters on entry
1202 uport = uart_port_ref(state);
1205 spin_lock_irq(&uport->lock);
1206 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1207 uart_enable_ms(uport);
1208 spin_unlock_irq(&uport->lock);
1210 add_wait_queue(&port->delta_msr_wait, &wait);
1212 spin_lock_irq(&uport->lock);
1213 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1214 spin_unlock_irq(&uport->lock);
1216 set_current_state(TASK_INTERRUPTIBLE);
1218 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1219 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1220 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1221 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1228 /* see if a signal did it */
1229 if (signal_pending(current)) {
1236 __set_current_state(TASK_RUNNING);
1237 remove_wait_queue(&port->delta_msr_wait, &wait);
1238 uart_port_deref(uport);
1244 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1245 * Return: write counters to the user passed counter struct
1246 * NB: both 1->0 and 0->1 transitions are counted except for
1247 * RI where only 0->1 is counted.
1249 static int uart_get_icount(struct tty_struct *tty,
1250 struct serial_icounter_struct *icount)
1252 struct uart_state *state = tty->driver_data;
1253 struct uart_icount cnow;
1254 struct uart_port *uport;
1256 uport = uart_port_ref(state);
1259 spin_lock_irq(&uport->lock);
1260 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1261 spin_unlock_irq(&uport->lock);
1262 uart_port_deref(uport);
1264 icount->cts = cnow.cts;
1265 icount->dsr = cnow.dsr;
1266 icount->rng = cnow.rng;
1267 icount->dcd = cnow.dcd;
1268 icount->rx = cnow.rx;
1269 icount->tx = cnow.tx;
1270 icount->frame = cnow.frame;
1271 icount->overrun = cnow.overrun;
1272 icount->parity = cnow.parity;
1273 icount->brk = cnow.brk;
1274 icount->buf_overrun = cnow.buf_overrun;
1279 static int uart_get_rs485_config(struct uart_port *port,
1280 struct serial_rs485 __user *rs485)
1282 unsigned long flags;
1283 struct serial_rs485 aux;
1285 spin_lock_irqsave(&port->lock, flags);
1287 spin_unlock_irqrestore(&port->lock, flags);
1289 if (copy_to_user(rs485, &aux, sizeof(aux)))
1295 static int uart_set_rs485_config(struct uart_port *port,
1296 struct serial_rs485 __user *rs485_user)
1298 struct serial_rs485 rs485;
1300 unsigned long flags;
1302 if (!port->rs485_config)
1305 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1308 /* pick sane settings if the user hasn't */
1309 if (!(rs485.flags & SER_RS485_RTS_ON_SEND) ==
1310 !(rs485.flags & SER_RS485_RTS_AFTER_SEND)) {
1311 dev_warn_ratelimited(port->dev,
1312 "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
1313 port->name, port->line);
1314 rs485.flags |= SER_RS485_RTS_ON_SEND;
1315 rs485.flags &= ~SER_RS485_RTS_AFTER_SEND;
1318 if (rs485.delay_rts_before_send > RS485_MAX_RTS_DELAY) {
1319 rs485.delay_rts_before_send = RS485_MAX_RTS_DELAY;
1320 dev_warn_ratelimited(port->dev,
1321 "%s (%d): RTS delay before sending clamped to %u ms\n",
1322 port->name, port->line, rs485.delay_rts_before_send);
1325 if (rs485.delay_rts_after_send > RS485_MAX_RTS_DELAY) {
1326 rs485.delay_rts_after_send = RS485_MAX_RTS_DELAY;
1327 dev_warn_ratelimited(port->dev,
1328 "%s (%d): RTS delay after sending clamped to %u ms\n",
1329 port->name, port->line, rs485.delay_rts_after_send);
1331 /* Return clean padding area to userspace */
1332 memset(rs485.padding, 0, sizeof(rs485.padding));
1334 spin_lock_irqsave(&port->lock, flags);
1335 ret = port->rs485_config(port, &rs485);
1337 port->rs485 = rs485;
1338 spin_unlock_irqrestore(&port->lock, flags);
1342 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1348 static int uart_get_iso7816_config(struct uart_port *port,
1349 struct serial_iso7816 __user *iso7816)
1351 unsigned long flags;
1352 struct serial_iso7816 aux;
1354 if (!port->iso7816_config)
1357 spin_lock_irqsave(&port->lock, flags);
1358 aux = port->iso7816;
1359 spin_unlock_irqrestore(&port->lock, flags);
1361 if (copy_to_user(iso7816, &aux, sizeof(aux)))
1367 static int uart_set_iso7816_config(struct uart_port *port,
1368 struct serial_iso7816 __user *iso7816_user)
1370 struct serial_iso7816 iso7816;
1372 unsigned long flags;
1374 if (!port->iso7816_config)
1377 if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1381 * There are 5 words reserved for future use. Check that userspace
1382 * doesn't put stuff in there to prevent breakages in the future.
1384 for (i = 0; i < 5; i++)
1385 if (iso7816.reserved[i])
1388 spin_lock_irqsave(&port->lock, flags);
1389 ret = port->iso7816_config(port, &iso7816);
1390 spin_unlock_irqrestore(&port->lock, flags);
1394 if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1401 * Called via sys_ioctl. We can use spin_lock_irq() here.
1404 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1406 struct uart_state *state = tty->driver_data;
1407 struct tty_port *port = &state->port;
1408 struct uart_port *uport;
1409 void __user *uarg = (void __user *)arg;
1410 int ret = -ENOIOCTLCMD;
1414 * These ioctls don't rely on the hardware to be present.
1418 down_write(&tty->termios_rwsem);
1419 ret = uart_do_autoconfig(tty, state);
1420 up_write(&tty->termios_rwsem);
1424 if (ret != -ENOIOCTLCMD)
1427 if (tty_io_error(tty)) {
1433 * The following should only be used when hardware is present.
1437 ret = uart_wait_modem_status(state, arg);
1441 if (ret != -ENOIOCTLCMD)
1444 mutex_lock(&port->mutex);
1445 uport = uart_port_check(state);
1447 if (!uport || tty_io_error(tty)) {
1453 * All these rely on hardware being present and need to be
1454 * protected against the tty being hung up.
1458 case TIOCSERGETLSR: /* Get line status register */
1459 ret = uart_get_lsr_info(tty, state, uarg);
1463 ret = uart_get_rs485_config(uport, uarg);
1467 ret = uart_set_rs485_config(uport, uarg);
1471 ret = uart_set_iso7816_config(state->uart_port, uarg);
1475 ret = uart_get_iso7816_config(state->uart_port, uarg);
1478 if (uport->ops->ioctl)
1479 ret = uport->ops->ioctl(uport, cmd, arg);
1483 mutex_unlock(&port->mutex);
1488 static void uart_set_ldisc(struct tty_struct *tty)
1490 struct uart_state *state = tty->driver_data;
1491 struct uart_port *uport;
1492 struct tty_port *port = &state->port;
1494 if (!tty_port_initialized(port))
1497 mutex_lock(&state->port.mutex);
1498 uport = uart_port_check(state);
1499 if (uport && uport->ops->set_ldisc)
1500 uport->ops->set_ldisc(uport, &tty->termios);
1501 mutex_unlock(&state->port.mutex);
1504 static void uart_set_termios(struct tty_struct *tty,
1505 struct ktermios *old_termios)
1507 struct uart_state *state = tty->driver_data;
1508 struct uart_port *uport;
1509 unsigned int cflag = tty->termios.c_cflag;
1510 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1511 bool sw_changed = false;
1513 mutex_lock(&state->port.mutex);
1514 uport = uart_port_check(state);
1519 * Drivers doing software flow control also need to know
1520 * about changes to these input settings.
1522 if (uport->flags & UPF_SOFT_FLOW) {
1523 iflag_mask |= IXANY|IXON|IXOFF;
1525 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1526 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1530 * These are the bits that are used to setup various
1531 * flags in the low level driver. We can ignore the Bfoo
1532 * bits in c_cflag; c_[io]speed will always be set
1533 * appropriately by set_termios() in tty_ioctl.c
1535 if ((cflag ^ old_termios->c_cflag) == 0 &&
1536 tty->termios.c_ospeed == old_termios->c_ospeed &&
1537 tty->termios.c_ispeed == old_termios->c_ispeed &&
1538 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1543 uart_change_speed(tty, state, old_termios);
1544 /* reload cflag from termios; port driver may have overridden flags */
1545 cflag = tty->termios.c_cflag;
1547 /* Handle transition to B0 status */
1548 if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1549 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1550 /* Handle transition away from B0 status */
1551 else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1552 unsigned int mask = TIOCM_DTR;
1554 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1556 uart_set_mctrl(uport, mask);
1559 mutex_unlock(&state->port.mutex);
1563 * Calls to uart_close() are serialised via the tty_lock in
1564 * drivers/tty/tty_io.c:tty_release()
1565 * drivers/tty/tty_io.c:do_tty_hangup()
1567 static void uart_close(struct tty_struct *tty, struct file *filp)
1569 struct uart_state *state = tty->driver_data;
1572 struct uart_driver *drv = tty->driver->driver_state;
1573 struct tty_port *port;
1575 state = drv->state + tty->index;
1576 port = &state->port;
1577 spin_lock_irq(&port->lock);
1579 spin_unlock_irq(&port->lock);
1583 pr_debug("uart_close(%d) called\n", tty->index);
1585 tty_port_close(tty->port, tty, filp);
1588 static void uart_tty_port_shutdown(struct tty_port *port)
1590 struct uart_state *state = container_of(port, struct uart_state, port);
1591 struct uart_port *uport = uart_port_check(state);
1595 * At this point, we stop accepting input. To do this, we
1596 * disable the receive line status interrupts.
1598 if (WARN(!uport, "detached port still initialized!\n"))
1601 spin_lock_irq(&uport->lock);
1602 uport->ops->stop_rx(uport);
1603 spin_unlock_irq(&uport->lock);
1605 uart_port_shutdown(port);
1608 * It's possible for shutdown to be called after suspend if we get
1609 * a DCD drop (hangup) at just the right time. Clear suspended bit so
1610 * we don't try to resume a port that has been shutdown.
1612 tty_port_set_suspended(port, 0);
1615 * Free the transmit buffer.
1617 spin_lock_irq(&uport->lock);
1618 buf = state->xmit.buf;
1619 state->xmit.buf = NULL;
1620 spin_unlock_irq(&uport->lock);
1622 free_page((unsigned long)buf);
1624 uart_change_pm(state, UART_PM_STATE_OFF);
1627 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1629 struct uart_state *state = tty->driver_data;
1630 struct uart_port *port;
1631 unsigned long char_time, expire;
1633 port = uart_port_ref(state);
1637 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1638 uart_port_deref(port);
1643 * Set the check interval to be 1/5 of the estimated time to
1644 * send a single character, and make it at least 1. The check
1645 * interval should also be less than the timeout.
1647 * Note: we have to use pretty tight timings here to satisfy
1650 char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
1652 if (timeout && timeout < char_time)
1653 char_time = timeout;
1655 if (!uart_cts_enabled(port)) {
1657 * If the transmitter hasn't cleared in twice the approximate
1658 * amount of time to send the entire FIFO, it probably won't
1659 * ever clear. This assumes the UART isn't doing flow
1660 * control, which is currently the case. Hence, if it ever
1661 * takes longer than port->timeout, this is probably due to a
1662 * UART bug of some kind. So, we clamp the timeout parameter at
1665 if (timeout == 0 || timeout > 2 * port->timeout)
1666 timeout = 2 * port->timeout;
1669 expire = jiffies + timeout;
1671 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1672 port->line, jiffies, expire);
1675 * Check whether the transmitter is empty every 'char_time'.
1676 * 'timeout' / 'expire' give us the maximum amount of time
1679 while (!port->ops->tx_empty(port)) {
1680 msleep_interruptible(jiffies_to_msecs(char_time));
1681 if (signal_pending(current))
1683 if (timeout && time_after(jiffies, expire))
1686 uart_port_deref(port);
1690 * Calls to uart_hangup() are serialised by the tty_lock in
1691 * drivers/tty/tty_io.c:do_tty_hangup()
1692 * This runs from a workqueue and can sleep for a _short_ time only.
1694 static void uart_hangup(struct tty_struct *tty)
1696 struct uart_state *state = tty->driver_data;
1697 struct tty_port *port = &state->port;
1698 struct uart_port *uport;
1699 unsigned long flags;
1701 pr_debug("uart_hangup(%d)\n", tty->index);
1703 mutex_lock(&port->mutex);
1704 uport = uart_port_check(state);
1705 WARN(!uport, "hangup of detached port!\n");
1707 if (tty_port_active(port)) {
1708 uart_flush_buffer(tty);
1709 uart_shutdown(tty, state);
1710 spin_lock_irqsave(&port->lock, flags);
1712 spin_unlock_irqrestore(&port->lock, flags);
1713 tty_port_set_active(port, 0);
1714 tty_port_tty_set(port, NULL);
1715 if (uport && !uart_console(uport))
1716 uart_change_pm(state, UART_PM_STATE_OFF);
1717 wake_up_interruptible(&port->open_wait);
1718 wake_up_interruptible(&port->delta_msr_wait);
1720 mutex_unlock(&port->mutex);
1723 /* uport == NULL if uart_port has already been removed */
1724 static void uart_port_shutdown(struct tty_port *port)
1726 struct uart_state *state = container_of(port, struct uart_state, port);
1727 struct uart_port *uport = uart_port_check(state);
1730 * clear delta_msr_wait queue to avoid mem leaks: we may free
1731 * the irq here so the queue might never be woken up. Note
1732 * that we won't end up waiting on delta_msr_wait again since
1733 * any outstanding file descriptors should be pointing at
1734 * hung_up_tty_fops now.
1736 wake_up_interruptible(&port->delta_msr_wait);
1739 /* Free the IRQ and disable the port. */
1740 uport->ops->shutdown(uport);
1742 /* Ensure that the IRQ handler isn't running on another CPU. */
1743 synchronize_irq(uport->irq);
1747 static int uart_carrier_raised(struct tty_port *port)
1749 struct uart_state *state = container_of(port, struct uart_state, port);
1750 struct uart_port *uport;
1753 uport = uart_port_ref(state);
1755 * Should never observe uport == NULL since checks for hangup should
1756 * abort the tty_port_block_til_ready() loop before checking for carrier
1757 * raised -- but report carrier raised if it does anyway so open will
1758 * continue and not sleep
1760 if (WARN_ON(!uport))
1762 spin_lock_irq(&uport->lock);
1763 uart_enable_ms(uport);
1764 mctrl = uport->ops->get_mctrl(uport);
1765 spin_unlock_irq(&uport->lock);
1766 uart_port_deref(uport);
1767 if (mctrl & TIOCM_CAR)
1772 static void uart_dtr_rts(struct tty_port *port, int raise)
1774 struct uart_state *state = container_of(port, struct uart_state, port);
1775 struct uart_port *uport;
1777 uport = uart_port_ref(state);
1780 uart_port_dtr_rts(uport, raise);
1781 uart_port_deref(uport);
1784 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1786 struct uart_driver *drv = driver->driver_state;
1787 struct uart_state *state = drv->state + tty->index;
1789 tty->driver_data = state;
1791 return tty_standard_install(driver, tty);
1795 * Calls to uart_open are serialised by the tty_lock in
1796 * drivers/tty/tty_io.c:tty_open()
1797 * Note that if this fails, then uart_close() _will_ be called.
1799 * In time, we want to scrap the "opening nonpresent ports"
1800 * behaviour and implement an alternative way for setserial
1801 * to set base addresses/ports/types. This will allow us to
1802 * get rid of a certain amount of extra tests.
1804 static int uart_open(struct tty_struct *tty, struct file *filp)
1806 struct uart_state *state = tty->driver_data;
1809 retval = tty_port_open(&state->port, tty, filp);
1816 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1818 struct uart_state *state = container_of(port, struct uart_state, port);
1819 struct uart_port *uport;
1822 uport = uart_port_check(state);
1823 if (!uport || uport->flags & UPF_DEAD)
1827 * Start up the serial port.
1829 ret = uart_startup(tty, state, 0);
1831 tty_port_set_active(port, 1);
1836 static const char *uart_type(struct uart_port *port)
1838 const char *str = NULL;
1840 if (port->ops->type)
1841 str = port->ops->type(port);
1849 #ifdef CONFIG_PROC_FS
1851 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1853 struct uart_state *state = drv->state + i;
1854 struct tty_port *port = &state->port;
1855 enum uart_pm_state pm_state;
1856 struct uart_port *uport;
1858 unsigned int status;
1861 mutex_lock(&port->mutex);
1862 uport = uart_port_check(state);
1866 mmio = uport->iotype >= UPIO_MEM;
1867 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
1868 uport->line, uart_type(uport),
1869 mmio ? "mmio:0x" : "port:",
1870 mmio ? (unsigned long long)uport->mapbase
1871 : (unsigned long long)uport->iobase,
1874 if (uport->type == PORT_UNKNOWN) {
1879 if (capable(CAP_SYS_ADMIN)) {
1880 pm_state = state->pm_state;
1881 if (pm_state != UART_PM_STATE_ON)
1882 uart_change_pm(state, UART_PM_STATE_ON);
1883 spin_lock_irq(&uport->lock);
1884 status = uport->ops->get_mctrl(uport);
1885 spin_unlock_irq(&uport->lock);
1886 if (pm_state != UART_PM_STATE_ON)
1887 uart_change_pm(state, pm_state);
1889 seq_printf(m, " tx:%d rx:%d",
1890 uport->icount.tx, uport->icount.rx);
1891 if (uport->icount.frame)
1892 seq_printf(m, " fe:%d", uport->icount.frame);
1893 if (uport->icount.parity)
1894 seq_printf(m, " pe:%d", uport->icount.parity);
1895 if (uport->icount.brk)
1896 seq_printf(m, " brk:%d", uport->icount.brk);
1897 if (uport->icount.overrun)
1898 seq_printf(m, " oe:%d", uport->icount.overrun);
1899 if (uport->icount.buf_overrun)
1900 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
1902 #define INFOBIT(bit, str) \
1903 if (uport->mctrl & (bit)) \
1904 strncat(stat_buf, (str), sizeof(stat_buf) - \
1905 strlen(stat_buf) - 2)
1906 #define STATBIT(bit, str) \
1907 if (status & (bit)) \
1908 strncat(stat_buf, (str), sizeof(stat_buf) - \
1909 strlen(stat_buf) - 2)
1913 INFOBIT(TIOCM_RTS, "|RTS");
1914 STATBIT(TIOCM_CTS, "|CTS");
1915 INFOBIT(TIOCM_DTR, "|DTR");
1916 STATBIT(TIOCM_DSR, "|DSR");
1917 STATBIT(TIOCM_CAR, "|CD");
1918 STATBIT(TIOCM_RNG, "|RI");
1922 seq_puts(m, stat_buf);
1928 mutex_unlock(&port->mutex);
1931 static int uart_proc_show(struct seq_file *m, void *v)
1933 struct tty_driver *ttydrv = m->private;
1934 struct uart_driver *drv = ttydrv->driver_state;
1937 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
1938 for (i = 0; i < drv->nr; i++)
1939 uart_line_info(m, drv, i);
1944 static void uart_port_spin_lock_init(struct uart_port *port)
1946 spin_lock_init(&port->lock);
1947 lockdep_set_class(&port->lock, &port_lock_key);
1950 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
1952 * uart_console_write - write a console message to a serial port
1953 * @port: the port to write the message
1954 * @s: array of characters
1955 * @count: number of characters in string to write
1956 * @putchar: function to write character to port
1958 void uart_console_write(struct uart_port *port, const char *s,
1960 void (*putchar)(struct uart_port *, unsigned char))
1964 for (i = 0; i < count; i++, s++) {
1966 putchar(port, '\r');
1970 EXPORT_SYMBOL_GPL(uart_console_write);
1973 * Check whether an invalid uart number has been specified, and
1974 * if so, search for the first available port that does have
1977 struct uart_port * __init
1978 uart_get_console(struct uart_port *ports, int nr, struct console *co)
1980 int idx = co->index;
1982 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1983 ports[idx].membase == NULL))
1984 for (idx = 0; idx < nr; idx++)
1985 if (ports[idx].iobase != 0 ||
1986 ports[idx].membase != NULL)
1995 * uart_parse_earlycon - Parse earlycon options
1996 * @p: ptr to 2nd field (ie., just beyond '<name>,')
1997 * @iotype: ptr for decoded iotype (out)
1998 * @addr: ptr for decoded mapbase/iobase (out)
1999 * @options: ptr for <options> field; NULL if not present (out)
2001 * Decodes earlycon kernel command line parameters of the form
2002 * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2003 * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2007 * earlycon=<name>,0x<addr>,<options>
2008 * console=<name>,0x<addr>,<options>
2010 * is also accepted; the returned @iotype will be UPIO_MEM.
2012 * Returns 0 on success or -EINVAL on failure
2014 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
2017 if (strncmp(p, "mmio,", 5) == 0) {
2020 } else if (strncmp(p, "mmio16,", 7) == 0) {
2021 *iotype = UPIO_MEM16;
2023 } else if (strncmp(p, "mmio32,", 7) == 0) {
2024 *iotype = UPIO_MEM32;
2026 } else if (strncmp(p, "mmio32be,", 9) == 0) {
2027 *iotype = UPIO_MEM32BE;
2029 } else if (strncmp(p, "mmio32native,", 13) == 0) {
2030 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2031 UPIO_MEM32BE : UPIO_MEM32;
2033 } else if (strncmp(p, "io,", 3) == 0) {
2034 *iotype = UPIO_PORT;
2036 } else if (strncmp(p, "0x", 2) == 0) {
2043 * Before you replace it with kstrtoull(), think about options separator
2044 * (',') it will not tolerate
2046 *addr = simple_strtoull(p, NULL, 0);
2054 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2057 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2058 * @options: pointer to option string
2059 * @baud: pointer to an 'int' variable for the baud rate.
2060 * @parity: pointer to an 'int' variable for the parity.
2061 * @bits: pointer to an 'int' variable for the number of data bits.
2062 * @flow: pointer to an 'int' variable for the flow control character.
2064 * uart_parse_options decodes a string containing the serial console
2065 * options. The format of the string is <baud><parity><bits><flow>,
2069 uart_parse_options(const char *options, int *baud, int *parity,
2070 int *bits, int *flow)
2072 const char *s = options;
2074 *baud = simple_strtoul(s, NULL, 10);
2075 while (*s >= '0' && *s <= '9')
2084 EXPORT_SYMBOL_GPL(uart_parse_options);
2087 * uart_set_options - setup the serial console parameters
2088 * @port: pointer to the serial ports uart_port structure
2089 * @co: console pointer
2091 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2092 * @bits: number of data bits
2093 * @flow: flow control character - 'r' (rts)
2096 uart_set_options(struct uart_port *port, struct console *co,
2097 int baud, int parity, int bits, int flow)
2099 struct ktermios termios;
2100 static struct ktermios dummy;
2103 * Ensure that the serial-console lock is initialised early.
2105 * Note that the console-enabled check is needed because of kgdboc,
2106 * which can end up calling uart_set_options() for an already enabled
2107 * console via tty_find_polling_driver() and uart_poll_init().
2109 if (!uart_console_enabled(port) && !port->console_reinit)
2110 uart_port_spin_lock_init(port);
2112 memset(&termios, 0, sizeof(struct ktermios));
2114 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2115 tty_termios_encode_baud_rate(&termios, baud, baud);
2118 termios.c_cflag |= CS7;
2120 termios.c_cflag |= CS8;
2124 termios.c_cflag |= PARODD;
2127 termios.c_cflag |= PARENB;
2132 termios.c_cflag |= CRTSCTS;
2135 * some uarts on other side don't support no flow control.
2136 * So we set * DTR in host uart to make them happy
2138 port->mctrl |= TIOCM_DTR;
2140 port->ops->set_termios(port, &termios, &dummy);
2142 * Allow the setting of the UART parameters with a NULL console
2146 co->cflag = termios.c_cflag;
2147 co->ispeed = termios.c_ispeed;
2148 co->ospeed = termios.c_ospeed;
2153 EXPORT_SYMBOL_GPL(uart_set_options);
2154 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2157 * uart_change_pm - set power state of the port
2159 * @state: port descriptor
2160 * @pm_state: new state
2162 * Locking: port->mutex has to be held
2164 static void uart_change_pm(struct uart_state *state,
2165 enum uart_pm_state pm_state)
2167 struct uart_port *port = uart_port_check(state);
2169 if (state->pm_state != pm_state) {
2170 if (port && port->ops->pm)
2171 port->ops->pm(port, pm_state, state->pm_state);
2172 state->pm_state = pm_state;
2177 struct uart_port *port;
2178 struct uart_driver *driver;
2181 static int serial_match_port(struct device *dev, void *data)
2183 struct uart_match *match = data;
2184 struct tty_driver *tty_drv = match->driver->tty_driver;
2185 dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2188 return dev->devt == devt; /* Actually, only one tty per port */
2191 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2193 struct uart_state *state = drv->state + uport->line;
2194 struct tty_port *port = &state->port;
2195 struct device *tty_dev;
2196 struct uart_match match = {uport, drv};
2198 mutex_lock(&port->mutex);
2200 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2201 if (tty_dev && device_may_wakeup(tty_dev)) {
2202 enable_irq_wake(uport->irq);
2203 put_device(tty_dev);
2204 mutex_unlock(&port->mutex);
2207 put_device(tty_dev);
2210 * Nothing to do if the console is not suspending
2211 * except stop_rx to prevent any asynchronous data
2212 * over RX line. However ensure that we will be
2213 * able to Re-start_rx later.
2215 if (!console_suspend_enabled && uart_console(uport)) {
2216 if (uport->ops->start_rx)
2217 uport->ops->stop_rx(uport);
2221 uport->suspended = 1;
2223 if (tty_port_initialized(port)) {
2224 const struct uart_ops *ops = uport->ops;
2228 tty_port_set_suspended(port, 1);
2229 tty_port_set_initialized(port, 0);
2231 spin_lock_irq(&uport->lock);
2232 ops->stop_tx(uport);
2233 ops->set_mctrl(uport, 0);
2234 /* save mctrl so it can be restored on resume */
2235 mctrl = uport->mctrl;
2237 ops->stop_rx(uport);
2238 spin_unlock_irq(&uport->lock);
2241 * Wait for the transmitter to empty.
2243 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2246 dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2249 ops->shutdown(uport);
2250 uport->mctrl = mctrl;
2254 * Disable the console device before suspending.
2256 if (uart_console(uport))
2257 console_stop(uport->cons);
2259 uart_change_pm(state, UART_PM_STATE_OFF);
2261 mutex_unlock(&port->mutex);
2265 EXPORT_SYMBOL(uart_suspend_port);
2267 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2269 struct uart_state *state = drv->state + uport->line;
2270 struct tty_port *port = &state->port;
2271 struct device *tty_dev;
2272 struct uart_match match = {uport, drv};
2273 struct ktermios termios;
2275 mutex_lock(&port->mutex);
2277 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2278 if (!uport->suspended && device_may_wakeup(tty_dev)) {
2279 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2280 disable_irq_wake(uport->irq);
2281 put_device(tty_dev);
2282 mutex_unlock(&port->mutex);
2285 put_device(tty_dev);
2286 uport->suspended = 0;
2289 * Re-enable the console device after suspending.
2291 if (uart_console(uport)) {
2293 * First try to use the console cflag setting.
2295 memset(&termios, 0, sizeof(struct ktermios));
2296 termios.c_cflag = uport->cons->cflag;
2297 termios.c_ispeed = uport->cons->ispeed;
2298 termios.c_ospeed = uport->cons->ospeed;
2301 * If that's unset, use the tty termios setting.
2303 if (port->tty && termios.c_cflag == 0)
2304 termios = port->tty->termios;
2306 if (console_suspend_enabled)
2307 uart_change_pm(state, UART_PM_STATE_ON);
2308 uport->ops->set_termios(uport, &termios, NULL);
2309 if (!console_suspend_enabled && uport->ops->start_rx)
2310 uport->ops->start_rx(uport);
2311 if (console_suspend_enabled)
2312 console_start(uport->cons);
2315 if (tty_port_suspended(port)) {
2316 const struct uart_ops *ops = uport->ops;
2319 uart_change_pm(state, UART_PM_STATE_ON);
2320 spin_lock_irq(&uport->lock);
2321 ops->set_mctrl(uport, 0);
2322 spin_unlock_irq(&uport->lock);
2323 if (console_suspend_enabled || !uart_console(uport)) {
2324 /* Protected by port mutex for now */
2325 struct tty_struct *tty = port->tty;
2327 ret = ops->startup(uport);
2330 uart_change_speed(tty, state, NULL);
2331 spin_lock_irq(&uport->lock);
2332 ops->set_mctrl(uport, uport->mctrl);
2333 ops->start_tx(uport);
2334 spin_unlock_irq(&uport->lock);
2335 tty_port_set_initialized(port, 1);
2338 * Failed to resume - maybe hardware went away?
2339 * Clear the "initialized" flag so we won't try
2340 * to call the low level drivers shutdown method.
2342 uart_shutdown(tty, state);
2346 tty_port_set_suspended(port, 0);
2349 mutex_unlock(&port->mutex);
2353 EXPORT_SYMBOL(uart_resume_port);
2356 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2360 switch (port->iotype) {
2362 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2365 snprintf(address, sizeof(address),
2366 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2374 snprintf(address, sizeof(address),
2375 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2378 strlcpy(address, "*unknown*", sizeof(address));
2382 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2383 port->dev ? dev_name(port->dev) : "",
2384 port->dev ? ": " : "",
2386 address, port->irq, port->uartclk / 16, uart_type(port));
2388 /* The magic multiplier feature is a bit obscure, so report it too. */
2389 if (port->flags & UPF_MAGIC_MULTIPLIER)
2390 pr_info("%s%s%s extra baud rates supported: %d, %d",
2391 port->dev ? dev_name(port->dev) : "",
2392 port->dev ? ": " : "",
2394 port->uartclk / 8, port->uartclk / 4);
2398 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2399 struct uart_port *port)
2404 * If there isn't a port here, don't do anything further.
2406 if (!port->iobase && !port->mapbase && !port->membase)
2410 * Now do the auto configuration stuff. Note that config_port
2411 * is expected to claim the resources and map the port for us.
2414 if (port->flags & UPF_AUTO_IRQ)
2415 flags |= UART_CONFIG_IRQ;
2416 if (port->flags & UPF_BOOT_AUTOCONF) {
2417 if (!(port->flags & UPF_FIXED_TYPE)) {
2418 port->type = PORT_UNKNOWN;
2419 flags |= UART_CONFIG_TYPE;
2421 port->ops->config_port(port, flags);
2424 if (port->type != PORT_UNKNOWN) {
2425 unsigned long flags;
2427 uart_report_port(drv, port);
2429 /* Power up port for set_mctrl() */
2430 uart_change_pm(state, UART_PM_STATE_ON);
2433 * Ensure that the modem control lines are de-activated.
2434 * keep the DTR setting that is set in uart_set_options()
2435 * We probably don't need a spinlock around this, but
2437 spin_lock_irqsave(&port->lock, flags);
2438 port->mctrl &= TIOCM_DTR;
2439 if (port->rs485.flags & SER_RS485_ENABLED &&
2440 !(port->rs485.flags & SER_RS485_RTS_AFTER_SEND))
2441 port->mctrl |= TIOCM_RTS;
2442 port->ops->set_mctrl(port, port->mctrl);
2443 spin_unlock_irqrestore(&port->lock, flags);
2446 * If this driver supports console, and it hasn't been
2447 * successfully registered yet, try to re-register it.
2448 * It may be that the port was not available.
2450 if (port->cons && !(port->cons->flags & CON_ENABLED))
2451 register_console(port->cons);
2454 * Power down all ports by default, except the
2455 * console if we have one.
2457 if (!uart_console(port))
2458 uart_change_pm(state, UART_PM_STATE_OFF);
2462 #ifdef CONFIG_CONSOLE_POLL
2464 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2466 struct uart_driver *drv = driver->driver_state;
2467 struct uart_state *state = drv->state + line;
2468 struct tty_port *tport;
2469 struct uart_port *port;
2476 tport = &state->port;
2477 mutex_lock(&tport->mutex);
2479 port = uart_port_check(state);
2480 if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2485 if (port->ops->poll_init) {
2487 * We don't set initialized as we only initialized the hw,
2488 * e.g. state->xmit is still uninitialized.
2490 if (!tty_port_initialized(tport))
2491 ret = port->ops->poll_init(port);
2494 if (!ret && options) {
2495 uart_parse_options(options, &baud, &parity, &bits, &flow);
2496 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2499 mutex_unlock(&tport->mutex);
2503 static int uart_poll_get_char(struct tty_driver *driver, int line)
2505 struct uart_driver *drv = driver->driver_state;
2506 struct uart_state *state = drv->state + line;
2507 struct uart_port *port;
2510 port = uart_port_ref(state);
2512 ret = port->ops->poll_get_char(port);
2513 uart_port_deref(port);
2519 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2521 struct uart_driver *drv = driver->driver_state;
2522 struct uart_state *state = drv->state + line;
2523 struct uart_port *port;
2525 port = uart_port_ref(state);
2530 port->ops->poll_put_char(port, '\r');
2531 port->ops->poll_put_char(port, ch);
2532 uart_port_deref(port);
2536 static const struct tty_operations uart_ops = {
2537 .install = uart_install,
2539 .close = uart_close,
2540 .write = uart_write,
2541 .put_char = uart_put_char,
2542 .flush_chars = uart_flush_chars,
2543 .write_room = uart_write_room,
2544 .chars_in_buffer= uart_chars_in_buffer,
2545 .flush_buffer = uart_flush_buffer,
2546 .ioctl = uart_ioctl,
2547 .throttle = uart_throttle,
2548 .unthrottle = uart_unthrottle,
2549 .send_xchar = uart_send_xchar,
2550 .set_termios = uart_set_termios,
2551 .set_ldisc = uart_set_ldisc,
2553 .start = uart_start,
2554 .hangup = uart_hangup,
2555 .break_ctl = uart_break_ctl,
2556 .wait_until_sent= uart_wait_until_sent,
2557 #ifdef CONFIG_PROC_FS
2558 .proc_show = uart_proc_show,
2560 .tiocmget = uart_tiocmget,
2561 .tiocmset = uart_tiocmset,
2562 .set_serial = uart_set_info_user,
2563 .get_serial = uart_get_info_user,
2564 .get_icount = uart_get_icount,
2565 #ifdef CONFIG_CONSOLE_POLL
2566 .poll_init = uart_poll_init,
2567 .poll_get_char = uart_poll_get_char,
2568 .poll_put_char = uart_poll_put_char,
2572 static const struct tty_port_operations uart_port_ops = {
2573 .carrier_raised = uart_carrier_raised,
2574 .dtr_rts = uart_dtr_rts,
2575 .activate = uart_port_activate,
2576 .shutdown = uart_tty_port_shutdown,
2580 * uart_register_driver - register a driver with the uart core layer
2581 * @drv: low level driver structure
2583 * Register a uart driver with the core driver. We in turn register
2584 * with the tty layer, and initialise the core driver per-port state.
2586 * We have a proc file in /proc/tty/driver which is named after the
2589 * drv->port should be NULL, and the per-port structures should be
2590 * registered using uart_add_one_port after this call has succeeded.
2592 int uart_register_driver(struct uart_driver *drv)
2594 struct tty_driver *normal;
2595 int i, retval = -ENOMEM;
2600 * Maybe we should be using a slab cache for this, especially if
2601 * we have a large number of ports to handle.
2603 drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2607 normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
2608 TTY_DRIVER_DYNAMIC_DEV);
2609 if (IS_ERR(normal)) {
2610 retval = PTR_ERR(normal);
2614 drv->tty_driver = normal;
2616 normal->driver_name = drv->driver_name;
2617 normal->name = drv->dev_name;
2618 normal->major = drv->major;
2619 normal->minor_start = drv->minor;
2620 normal->type = TTY_DRIVER_TYPE_SERIAL;
2621 normal->subtype = SERIAL_TYPE_NORMAL;
2622 normal->init_termios = tty_std_termios;
2623 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2624 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2625 normal->driver_state = drv;
2626 tty_set_operations(normal, &uart_ops);
2629 * Initialise the UART state(s).
2631 for (i = 0; i < drv->nr; i++) {
2632 struct uart_state *state = drv->state + i;
2633 struct tty_port *port = &state->port;
2635 tty_port_init(port);
2636 port->ops = &uart_port_ops;
2639 retval = tty_register_driver(normal);
2643 for (i = 0; i < drv->nr; i++)
2644 tty_port_destroy(&drv->state[i].port);
2645 tty_driver_kref_put(normal);
2651 EXPORT_SYMBOL(uart_register_driver);
2654 * uart_unregister_driver - remove a driver from the uart core layer
2655 * @drv: low level driver structure
2657 * Remove all references to a driver from the core driver. The low
2658 * level driver must have removed all its ports via the
2659 * uart_remove_one_port() if it registered them with uart_add_one_port().
2660 * (ie, drv->port == NULL)
2662 void uart_unregister_driver(struct uart_driver *drv)
2664 struct tty_driver *p = drv->tty_driver;
2667 tty_unregister_driver(p);
2668 tty_driver_kref_put(p);
2669 for (i = 0; i < drv->nr; i++)
2670 tty_port_destroy(&drv->state[i].port);
2673 drv->tty_driver = NULL;
2675 EXPORT_SYMBOL(uart_unregister_driver);
2677 struct tty_driver *uart_console_device(struct console *co, int *index)
2679 struct uart_driver *p = co->data;
2681 return p->tty_driver;
2683 EXPORT_SYMBOL_GPL(uart_console_device);
2685 static ssize_t uartclk_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.baud_base * 16);
2695 static ssize_t type_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.type);
2705 static ssize_t line_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.line);
2715 static ssize_t port_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);
2720 unsigned long ioaddr;
2722 uart_get_info(port, &tmp);
2724 if (HIGH_BITS_OFFSET)
2725 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2726 return sprintf(buf, "0x%lX\n", ioaddr);
2729 static ssize_t irq_show(struct device *dev,
2730 struct device_attribute *attr, char *buf)
2732 struct serial_struct tmp;
2733 struct tty_port *port = dev_get_drvdata(dev);
2735 uart_get_info(port, &tmp);
2736 return sprintf(buf, "%d\n", tmp.irq);
2739 static ssize_t flags_show(struct device *dev,
2740 struct device_attribute *attr, char *buf)
2742 struct serial_struct tmp;
2743 struct tty_port *port = dev_get_drvdata(dev);
2745 uart_get_info(port, &tmp);
2746 return sprintf(buf, "0x%X\n", tmp.flags);
2749 static ssize_t xmit_fifo_size_show(struct device *dev,
2750 struct device_attribute *attr, char *buf)
2752 struct serial_struct tmp;
2753 struct tty_port *port = dev_get_drvdata(dev);
2755 uart_get_info(port, &tmp);
2756 return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2759 static ssize_t close_delay_show(struct device *dev,
2760 struct device_attribute *attr, char *buf)
2762 struct serial_struct tmp;
2763 struct tty_port *port = dev_get_drvdata(dev);
2765 uart_get_info(port, &tmp);
2766 return sprintf(buf, "%d\n", tmp.close_delay);
2769 static ssize_t closing_wait_show(struct device *dev,
2770 struct device_attribute *attr, char *buf)
2772 struct serial_struct tmp;
2773 struct tty_port *port = dev_get_drvdata(dev);
2775 uart_get_info(port, &tmp);
2776 return sprintf(buf, "%d\n", tmp.closing_wait);
2779 static ssize_t custom_divisor_show(struct device *dev,
2780 struct device_attribute *attr, char *buf)
2782 struct serial_struct tmp;
2783 struct tty_port *port = dev_get_drvdata(dev);
2785 uart_get_info(port, &tmp);
2786 return sprintf(buf, "%d\n", tmp.custom_divisor);
2789 static ssize_t io_type_show(struct device *dev,
2790 struct device_attribute *attr, char *buf)
2792 struct serial_struct tmp;
2793 struct tty_port *port = dev_get_drvdata(dev);
2795 uart_get_info(port, &tmp);
2796 return sprintf(buf, "%d\n", tmp.io_type);
2799 static ssize_t iomem_base_show(struct device *dev,
2800 struct device_attribute *attr, char *buf)
2802 struct serial_struct tmp;
2803 struct tty_port *port = dev_get_drvdata(dev);
2805 uart_get_info(port, &tmp);
2806 return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
2809 static ssize_t iomem_reg_shift_show(struct device *dev,
2810 struct device_attribute *attr, char *buf)
2812 struct serial_struct tmp;
2813 struct tty_port *port = dev_get_drvdata(dev);
2815 uart_get_info(port, &tmp);
2816 return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
2819 static ssize_t console_show(struct device *dev,
2820 struct device_attribute *attr, char *buf)
2822 struct tty_port *port = dev_get_drvdata(dev);
2823 struct uart_state *state = container_of(port, struct uart_state, port);
2824 struct uart_port *uport;
2825 bool console = false;
2827 mutex_lock(&port->mutex);
2828 uport = uart_port_check(state);
2830 console = uart_console_enabled(uport);
2831 mutex_unlock(&port->mutex);
2833 return sprintf(buf, "%c\n", console ? 'Y' : 'N');
2836 static ssize_t console_store(struct device *dev,
2837 struct device_attribute *attr, const char *buf, size_t count)
2839 struct tty_port *port = dev_get_drvdata(dev);
2840 struct uart_state *state = container_of(port, struct uart_state, port);
2841 struct uart_port *uport;
2842 bool oldconsole, newconsole;
2845 ret = kstrtobool(buf, &newconsole);
2849 mutex_lock(&port->mutex);
2850 uport = uart_port_check(state);
2852 oldconsole = uart_console_enabled(uport);
2853 if (oldconsole && !newconsole) {
2854 ret = unregister_console(uport->cons);
2855 } else if (!oldconsole && newconsole) {
2856 if (uart_console(uport)) {
2857 uport->console_reinit = 1;
2858 register_console(uport->cons);
2866 mutex_unlock(&port->mutex);
2868 return ret < 0 ? ret : count;
2871 static DEVICE_ATTR_RO(uartclk);
2872 static DEVICE_ATTR_RO(type);
2873 static DEVICE_ATTR_RO(line);
2874 static DEVICE_ATTR_RO(port);
2875 static DEVICE_ATTR_RO(irq);
2876 static DEVICE_ATTR_RO(flags);
2877 static DEVICE_ATTR_RO(xmit_fifo_size);
2878 static DEVICE_ATTR_RO(close_delay);
2879 static DEVICE_ATTR_RO(closing_wait);
2880 static DEVICE_ATTR_RO(custom_divisor);
2881 static DEVICE_ATTR_RO(io_type);
2882 static DEVICE_ATTR_RO(iomem_base);
2883 static DEVICE_ATTR_RO(iomem_reg_shift);
2884 static DEVICE_ATTR_RW(console);
2886 static struct attribute *tty_dev_attrs[] = {
2887 &dev_attr_uartclk.attr,
2888 &dev_attr_type.attr,
2889 &dev_attr_line.attr,
2890 &dev_attr_port.attr,
2892 &dev_attr_flags.attr,
2893 &dev_attr_xmit_fifo_size.attr,
2894 &dev_attr_close_delay.attr,
2895 &dev_attr_closing_wait.attr,
2896 &dev_attr_custom_divisor.attr,
2897 &dev_attr_io_type.attr,
2898 &dev_attr_iomem_base.attr,
2899 &dev_attr_iomem_reg_shift.attr,
2900 &dev_attr_console.attr,
2904 static const struct attribute_group tty_dev_attr_group = {
2905 .attrs = tty_dev_attrs,
2909 * uart_add_one_port - attach a driver-defined port structure
2910 * @drv: pointer to the uart low level driver structure for this port
2911 * @uport: uart port structure to use for this port.
2913 * Context: task context, might sleep
2915 * This allows the driver to register its own uart_port structure
2916 * with the core driver. The main purpose is to allow the low
2917 * level uart drivers to expand uart_port, rather than having yet
2918 * more levels of structures.
2920 int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
2922 struct uart_state *state;
2923 struct tty_port *port;
2925 struct device *tty_dev;
2928 if (uport->line >= drv->nr)
2931 state = drv->state + uport->line;
2932 port = &state->port;
2934 mutex_lock(&port_mutex);
2935 mutex_lock(&port->mutex);
2936 if (state->uart_port) {
2941 /* Link the port to the driver state table and vice versa */
2942 atomic_set(&state->refcount, 1);
2943 init_waitqueue_head(&state->remove_wait);
2944 state->uart_port = uport;
2945 uport->state = state;
2947 state->pm_state = UART_PM_STATE_UNDEFINED;
2948 uport->cons = drv->cons;
2949 uport->minor = drv->tty_driver->minor_start + uport->line;
2950 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
2951 drv->tty_driver->name_base + uport->line);
2958 * If this port is in use as a console then the spinlock is already
2961 if (!uart_console_enabled(uport))
2962 uart_port_spin_lock_init(uport);
2964 if (uport->cons && uport->dev)
2965 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
2967 tty_port_link_device(port, drv->tty_driver, uport->line);
2968 uart_configure_port(drv, state, uport);
2970 port->console = uart_console(uport);
2973 if (uport->attr_group)
2976 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
2978 if (!uport->tty_groups) {
2982 uport->tty_groups[0] = &tty_dev_attr_group;
2983 if (uport->attr_group)
2984 uport->tty_groups[1] = uport->attr_group;
2987 * Register the port whether it's detected or not. This allows
2988 * setserial to be used to alter this port's parameters.
2990 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
2991 uport->line, uport->dev, port, uport->tty_groups);
2992 if (!IS_ERR(tty_dev)) {
2993 device_set_wakeup_capable(tty_dev, 1);
2995 dev_err(uport->dev, "Cannot register tty device on line %d\n",
3000 * Ensure UPF_DEAD is not set.
3002 uport->flags &= ~UPF_DEAD;
3005 mutex_unlock(&port->mutex);
3006 mutex_unlock(&port_mutex);
3010 EXPORT_SYMBOL(uart_add_one_port);
3013 * uart_remove_one_port - detach a driver defined port structure
3014 * @drv: pointer to the uart low level driver structure for this port
3015 * @uport: uart port structure for this port
3017 * Context: task context, might sleep
3019 * This unhooks (and hangs up) the specified port structure from the
3020 * core driver. No further calls will be made to the low-level code
3023 int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
3025 struct uart_state *state = drv->state + uport->line;
3026 struct tty_port *port = &state->port;
3027 struct uart_port *uart_port;
3028 struct tty_struct *tty;
3031 mutex_lock(&port_mutex);
3034 * Mark the port "dead" - this prevents any opens from
3035 * succeeding while we shut down the port.
3037 mutex_lock(&port->mutex);
3038 uart_port = uart_port_check(state);
3039 if (uart_port != uport)
3040 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
3044 mutex_unlock(&port->mutex);
3048 uport->flags |= UPF_DEAD;
3049 mutex_unlock(&port->mutex);
3052 * Remove the devices from the tty layer
3054 tty_port_unregister_device(port, drv->tty_driver, uport->line);
3056 tty = tty_port_tty_get(port);
3058 tty_vhangup(port->tty);
3063 * If the port is used as a console, unregister it
3065 if (uart_console(uport))
3066 unregister_console(uport->cons);
3069 * Free the port IO and memory resources, if any.
3071 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3072 uport->ops->release_port(uport);
3073 kfree(uport->tty_groups);
3077 * Indicate that there isn't a port here anymore.
3079 uport->type = PORT_UNKNOWN;
3081 mutex_lock(&port->mutex);
3082 WARN_ON(atomic_dec_return(&state->refcount) < 0);
3083 wait_event(state->remove_wait, !atomic_read(&state->refcount));
3084 state->uart_port = NULL;
3085 mutex_unlock(&port->mutex);
3087 mutex_unlock(&port_mutex);
3091 EXPORT_SYMBOL(uart_remove_one_port);
3094 * Are the two ports equivalent?
3096 bool uart_match_port(const struct uart_port *port1,
3097 const struct uart_port *port2)
3099 if (port1->iotype != port2->iotype)
3102 switch (port1->iotype) {
3104 return port1->iobase == port2->iobase;
3106 return port1->iobase == port2->iobase &&
3107 port1->hub6 == port2->hub6;
3114 return port1->mapbase == port2->mapbase;
3119 EXPORT_SYMBOL(uart_match_port);
3122 * uart_handle_dcd_change - handle a change of carrier detect state
3123 * @uport: uart_port structure for the open port
3124 * @status: new carrier detect status, nonzero if active
3126 * Caller must hold uport->lock
3128 void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
3130 struct tty_port *port = &uport->state->port;
3131 struct tty_struct *tty = port->tty;
3132 struct tty_ldisc *ld;
3134 lockdep_assert_held_once(&uport->lock);
3137 ld = tty_ldisc_ref(tty);
3139 if (ld->ops->dcd_change)
3140 ld->ops->dcd_change(tty, status);
3141 tty_ldisc_deref(ld);
3145 uport->icount.dcd++;
3147 if (uart_dcd_enabled(uport)) {
3149 wake_up_interruptible(&port->open_wait);
3154 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3157 * uart_handle_cts_change - handle a change of clear-to-send state
3158 * @uport: uart_port structure for the open port
3159 * @status: new clear to send status, nonzero if active
3161 * Caller must hold uport->lock
3163 void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
3165 lockdep_assert_held_once(&uport->lock);
3167 uport->icount.cts++;
3169 if (uart_softcts_mode(uport)) {
3170 if (uport->hw_stopped) {
3172 uport->hw_stopped = 0;
3173 uport->ops->start_tx(uport);
3174 uart_write_wakeup(uport);
3178 uport->hw_stopped = 1;
3179 uport->ops->stop_tx(uport);
3185 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3188 * uart_insert_char - push a char to the uart layer
3190 * User is responsible to call tty_flip_buffer_push when they are done with
3193 * @port: corresponding port
3194 * @status: state of the serial port RX buffer (LSR for 8250)
3195 * @overrun: mask of overrun bits in @status
3196 * @ch: character to push
3197 * @flag: flag for the character (see TTY_NORMAL and friends)
3199 void uart_insert_char(struct uart_port *port, unsigned int status,
3200 unsigned int overrun, unsigned int ch, unsigned int flag)
3202 struct tty_port *tport = &port->state->port;
3204 if ((status & port->ignore_status_mask & ~overrun) == 0)
3205 if (tty_insert_flip_char(tport, ch, flag) == 0)
3206 ++port->icount.buf_overrun;
3209 * Overrun is special. Since it's reported immediately,
3210 * it doesn't affect the current character.
3212 if (status & ~port->ignore_status_mask & overrun)
3213 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3214 ++port->icount.buf_overrun;
3216 EXPORT_SYMBOL_GPL(uart_insert_char);
3218 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3219 static const char sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3221 static void uart_sysrq_on(struct work_struct *w)
3223 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3225 sysrq_toggle_support(1);
3226 pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3227 sysrq_toggle_seq_len, sysrq_toggle_seq);
3229 static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3232 * uart_try_toggle_sysrq - Enables SysRq from serial line
3233 * @port: uart_port structure where char(s) after BREAK met
3234 * @ch: new character in the sequence after received BREAK
3236 * Enables magic SysRq when the required sequence is met on port
3237 * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3239 * Returns false if @ch is out of enabling sequence and should be
3240 * handled some other way, true if @ch was consumed.
3242 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
3244 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3246 if (!sysrq_toggle_seq_len)
3249 BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3250 if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3251 port->sysrq_seq = 0;
3255 if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3256 port->sysrq = jiffies + SYSRQ_TIMEOUT;
3260 schedule_work(&sysrq_enable_work);
3265 EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3269 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3270 * @port: uart device's target port
3272 * This function implements the device tree binding described in
3273 * Documentation/devicetree/bindings/serial/rs485.txt.
3275 int uart_get_rs485_mode(struct uart_port *port)
3277 struct serial_rs485 *rs485conf = &port->rs485;
3278 struct device *dev = port->dev;
3282 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3285 rs485conf->delay_rts_before_send = rs485_delay[0];
3286 rs485conf->delay_rts_after_send = rs485_delay[1];
3288 rs485conf->delay_rts_before_send = 0;
3289 rs485conf->delay_rts_after_send = 0;
3293 * Clear full-duplex and enabled flags, set RTS polarity to active high
3294 * to get to a defined state with the following properties:
3296 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3297 SER_RS485_TERMINATE_BUS |
3298 SER_RS485_RTS_AFTER_SEND);
3299 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3301 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3302 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3304 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3305 rs485conf->flags |= SER_RS485_ENABLED;
3307 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3308 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3309 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3313 * Disabling termination by default is the safe choice: Else if many
3314 * bus participants enable it, no communication is possible at all.
3315 * Works fine for short cables and users may enable for longer cables.
3317 port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
3319 if (IS_ERR(port->rs485_term_gpio)) {
3320 ret = PTR_ERR(port->rs485_term_gpio);
3321 port->rs485_term_gpio = NULL;
3322 return dev_err_probe(dev, ret, "Cannot get rs485-term-gpios\n");
3327 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3329 MODULE_DESCRIPTION("Serial driver core");
3330 MODULE_LICENSE("GPL");