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>
18 #include <linux/kernel.h>
20 #include <linux/pm_runtime.h>
21 #include <linux/proc_fs.h>
22 #include <linux/seq_file.h>
23 #include <linux/device.h>
24 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
25 #include <linux/serial_core.h>
26 #include <linux/sysrq.h>
27 #include <linux/delay.h>
28 #include <linux/mutex.h>
29 #include <linux/math64.h>
30 #include <linux/security.h>
32 #include <linux/irq.h>
33 #include <linux/uaccess.h>
35 #include "serial_base.h"
38 * This is used to lock changes in serial line configuration.
40 static DEFINE_MUTEX(port_mutex);
43 * lockdep: port->lock is initialized in two places, but we
44 * want only one lock-class:
46 static struct lock_class_key port_lock_key;
48 #define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
51 * Max time with active RTS before/after data is sent.
53 #define RS485_MAX_RTS_DELAY 100 /* msecs */
55 static void uart_change_pm(struct uart_state *state,
56 enum uart_pm_state pm_state);
58 static void uart_port_shutdown(struct tty_port *port);
60 static int uart_dcd_enabled(struct uart_port *uport)
62 return !!(uport->status & UPSTAT_DCD_ENABLE);
65 static inline struct uart_port *uart_port_ref(struct uart_state *state)
67 if (atomic_add_unless(&state->refcount, 1, 0))
68 return state->uart_port;
72 static inline void uart_port_deref(struct uart_port *uport)
74 if (atomic_dec_and_test(&uport->state->refcount))
75 wake_up(&uport->state->remove_wait);
78 #define uart_port_lock(state, flags) \
80 struct uart_port *__uport = uart_port_ref(state); \
82 spin_lock_irqsave(&__uport->lock, flags); \
86 #define uart_port_unlock(uport, flags) \
88 struct uart_port *__uport = uport; \
90 spin_unlock_irqrestore(&__uport->lock, flags); \
91 uart_port_deref(__uport); \
95 static inline struct uart_port *uart_port_check(struct uart_state *state)
97 lockdep_assert_held(&state->port.mutex);
98 return state->uart_port;
102 * uart_write_wakeup - schedule write processing
103 * @port: port to be processed
105 * This routine is used by the interrupt handler to schedule processing in the
106 * software interrupt portion of the driver. A driver is expected to call this
107 * function when the number of characters in the transmit buffer have dropped
110 * Locking: @port->lock should be held
112 void uart_write_wakeup(struct uart_port *port)
114 struct uart_state *state = port->state;
116 * This means you called this function _after_ the port was
117 * closed. No cookie for you.
120 tty_port_tty_wakeup(&state->port);
122 EXPORT_SYMBOL(uart_write_wakeup);
124 static void uart_stop(struct tty_struct *tty)
126 struct uart_state *state = tty->driver_data;
127 struct uart_port *port;
130 port = uart_port_lock(state, flags);
132 port->ops->stop_tx(port);
133 uart_port_unlock(port, flags);
136 static void __uart_start(struct tty_struct *tty)
138 struct uart_state *state = tty->driver_data;
139 struct uart_port *port = state->uart_port;
140 struct serial_port_device *port_dev;
143 if (!port || port->flags & UPF_DEAD || uart_tx_stopped(port))
146 port_dev = port->port_dev;
148 /* Increment the runtime PM usage count for the active check below */
149 err = pm_runtime_get(&port_dev->dev);
151 pm_runtime_put_noidle(&port_dev->dev);
156 * Start TX if enabled, and kick runtime PM. If the device is not
157 * enabled, serial_port_runtime_resume() calls start_tx() again
158 * after enabling the device.
160 if (pm_runtime_active(&port_dev->dev))
161 port->ops->start_tx(port);
162 pm_runtime_mark_last_busy(&port_dev->dev);
163 pm_runtime_put_autosuspend(&port_dev->dev);
166 static void uart_start(struct tty_struct *tty)
168 struct uart_state *state = tty->driver_data;
169 struct uart_port *port;
172 port = uart_port_lock(state, flags);
174 uart_port_unlock(port, flags);
178 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
183 spin_lock_irqsave(&port->lock, flags);
185 port->mctrl = (old & ~clear) | set;
186 if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))
187 port->ops->set_mctrl(port, port->mctrl);
188 spin_unlock_irqrestore(&port->lock, flags);
191 #define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
192 #define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
194 static void uart_port_dtr_rts(struct uart_port *uport, bool active)
197 uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
199 uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
202 /* Caller holds port mutex */
203 static void uart_change_line_settings(struct tty_struct *tty, struct uart_state *state,
204 const struct ktermios *old_termios)
206 struct uart_port *uport = uart_port_check(state);
207 struct ktermios *termios;
211 * If we have no tty, termios, or the port does not exist,
212 * then we can't set the parameters for this port.
214 if (!tty || uport->type == PORT_UNKNOWN)
217 termios = &tty->termios;
218 uport->ops->set_termios(uport, termios, old_termios);
221 * Set modem status enables based on termios cflag
223 spin_lock_irq(&uport->lock);
224 if (termios->c_cflag & CRTSCTS)
225 uport->status |= UPSTAT_CTS_ENABLE;
227 uport->status &= ~UPSTAT_CTS_ENABLE;
229 if (termios->c_cflag & CLOCAL)
230 uport->status &= ~UPSTAT_DCD_ENABLE;
232 uport->status |= UPSTAT_DCD_ENABLE;
234 /* reset sw-assisted CTS flow control based on (possibly) new mode */
235 old_hw_stopped = uport->hw_stopped;
236 uport->hw_stopped = uart_softcts_mode(uport) &&
237 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
238 if (uport->hw_stopped != old_hw_stopped) {
240 uport->ops->stop_tx(uport);
244 spin_unlock_irq(&uport->lock);
248 * Startup the port. This will be called once per open. All calls
249 * will be serialised by the per-port mutex.
251 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
254 struct uart_port *uport = uart_port_check(state);
259 if (uport->type == PORT_UNKNOWN)
263 * Make sure the device is in D0 state.
265 uart_change_pm(state, UART_PM_STATE_ON);
268 * Initialise and allocate the transmit and temporary
271 page = get_zeroed_page(GFP_KERNEL);
275 uart_port_lock(state, flags);
276 if (!state->xmit.buf) {
277 state->xmit.buf = (unsigned char *) page;
278 uart_circ_clear(&state->xmit);
279 uart_port_unlock(uport, flags);
281 uart_port_unlock(uport, flags);
283 * Do not free() the page under the port lock, see
289 retval = uport->ops->startup(uport);
291 if (uart_console(uport) && uport->cons->cflag) {
292 tty->termios.c_cflag = uport->cons->cflag;
293 tty->termios.c_ispeed = uport->cons->ispeed;
294 tty->termios.c_ospeed = uport->cons->ospeed;
295 uport->cons->cflag = 0;
296 uport->cons->ispeed = 0;
297 uport->cons->ospeed = 0;
300 * Initialise the hardware port settings.
302 uart_change_line_settings(tty, state, NULL);
305 * Setup the RTS and DTR signals once the
306 * port is open and ready to respond.
308 if (init_hw && C_BAUD(tty))
309 uart_port_dtr_rts(uport, true);
313 * This is to allow setserial on this port. People may want to set
314 * port/irq/type and then reconfigure the port properly if it failed
317 if (retval && capable(CAP_SYS_ADMIN))
323 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
326 struct tty_port *port = &state->port;
329 if (tty_port_initialized(port))
332 retval = uart_port_startup(tty, state, init_hw);
334 set_bit(TTY_IO_ERROR, &tty->flags);
340 * This routine will shutdown a serial port; interrupts are disabled, and
341 * DTR is dropped if the hangup on close termio flag is on. Calls to
342 * uart_shutdown are serialised by the per-port semaphore.
344 * uport == NULL if uart_port has already been removed
346 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
348 struct uart_port *uport = uart_port_check(state);
349 struct tty_port *port = &state->port;
351 char *xmit_buf = NULL;
354 * Set the TTY IO error marker
357 set_bit(TTY_IO_ERROR, &tty->flags);
359 if (tty_port_initialized(port)) {
360 tty_port_set_initialized(port, false);
363 * Turn off DTR and RTS early.
365 if (uport && uart_console(uport) && tty) {
366 uport->cons->cflag = tty->termios.c_cflag;
367 uport->cons->ispeed = tty->termios.c_ispeed;
368 uport->cons->ospeed = tty->termios.c_ospeed;
371 if (!tty || C_HUPCL(tty))
372 uart_port_dtr_rts(uport, false);
374 uart_port_shutdown(port);
378 * It's possible for shutdown to be called after suspend if we get
379 * a DCD drop (hangup) at just the right time. Clear suspended bit so
380 * we don't try to resume a port that has been shutdown.
382 tty_port_set_suspended(port, false);
385 * Do not free() the transmit buffer page under the port lock since
386 * this can create various circular locking scenarios. For instance,
387 * console driver may need to allocate/free a debug object, which
388 * can endup in printk() recursion.
390 uart_port_lock(state, flags);
391 xmit_buf = state->xmit.buf;
392 state->xmit.buf = NULL;
393 uart_port_unlock(uport, flags);
395 free_page((unsigned long)xmit_buf);
399 * uart_update_timeout - update per-port frame timing information
400 * @port: uart_port structure describing the port
401 * @cflag: termios cflag value
402 * @baud: speed of the port
404 * Set the @port frame timing information from which the FIFO timeout value is
405 * derived. The @cflag value should reflect the actual hardware settings as
406 * number of bits, parity, stop bits and baud rate is taken into account here.
408 * Locking: caller is expected to take @port->lock
411 uart_update_timeout(struct uart_port *port, unsigned int cflag,
414 unsigned int size = tty_get_frame_size(cflag);
417 frame_time = (u64)size * NSEC_PER_SEC;
418 port->frame_time = DIV64_U64_ROUND_UP(frame_time, baud);
420 EXPORT_SYMBOL(uart_update_timeout);
423 * uart_get_baud_rate - return baud rate for a particular port
424 * @port: uart_port structure describing the port in question.
425 * @termios: desired termios settings
426 * @old: old termios (or %NULL)
427 * @min: minimum acceptable baud rate
428 * @max: maximum acceptable baud rate
430 * Decode the termios structure into a numeric baud rate, taking account of the
431 * magic 38400 baud rate (with spd_* flags), and mapping the %B0 rate to 9600
434 * If the new baud rate is invalid, try the @old termios setting. If it's still
435 * invalid, we try 9600 baud.
437 * The @termios structure is updated to reflect the baud rate we're actually
438 * going to be using. Don't do this for the case where B0 is requested ("hang
441 * Locking: caller dependent
444 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
445 const struct ktermios *old, unsigned int min, unsigned int max)
449 unsigned int altbaud;
451 upf_t flags = port->flags & UPF_SPD_MASK;
471 for (try = 0; try < 2; try++) {
472 baud = tty_termios_baud_rate(termios);
475 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
478 if (try == 0 && baud == 38400)
482 * Special case: B0 rate.
489 if (baud >= min && baud <= max)
493 * Oops, the quotient was zero. Try again with
494 * the old baud rate if possible.
496 termios->c_cflag &= ~CBAUD;
498 baud = tty_termios_baud_rate(old);
500 tty_termios_encode_baud_rate(termios,
507 * As a last resort, if the range cannot be met then clip to
508 * the nearest chip supported rate.
512 tty_termios_encode_baud_rate(termios,
515 tty_termios_encode_baud_rate(termios,
519 /* Should never happen */
523 EXPORT_SYMBOL(uart_get_baud_rate);
526 * uart_get_divisor - return uart clock divisor
527 * @port: uart_port structure describing the port
528 * @baud: desired baud rate
530 * Calculate the divisor (baud_base / baud) for the specified @baud,
531 * appropriately rounded.
533 * If 38400 baud and custom divisor is selected, return the custom divisor
536 * Locking: caller dependent
539 uart_get_divisor(struct uart_port *port, unsigned int baud)
544 * Old custom speed handling.
546 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
547 quot = port->custom_divisor;
549 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
553 EXPORT_SYMBOL(uart_get_divisor);
555 static int uart_put_char(struct tty_struct *tty, unsigned char c)
557 struct uart_state *state = tty->driver_data;
558 struct uart_port *port;
559 struct circ_buf *circ;
564 port = uart_port_lock(state, flags);
566 uart_port_unlock(port, flags);
570 if (port && uart_circ_chars_free(circ) != 0) {
571 circ->buf[circ->head] = c;
572 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
575 uart_port_unlock(port, flags);
579 static void uart_flush_chars(struct tty_struct *tty)
584 static int uart_write(struct tty_struct *tty,
585 const unsigned char *buf, int count)
587 struct uart_state *state = tty->driver_data;
588 struct uart_port *port;
589 struct circ_buf *circ;
594 * This means you called this function _after_ the port was
595 * closed. No cookie for you.
602 port = uart_port_lock(state, flags);
605 uart_port_unlock(port, flags);
610 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
615 memcpy(circ->buf + circ->head, buf, c);
616 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
623 uart_port_unlock(port, flags);
627 static unsigned int uart_write_room(struct tty_struct *tty)
629 struct uart_state *state = tty->driver_data;
630 struct uart_port *port;
634 port = uart_port_lock(state, flags);
635 ret = uart_circ_chars_free(&state->xmit);
636 uart_port_unlock(port, flags);
640 static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
642 struct uart_state *state = tty->driver_data;
643 struct uart_port *port;
647 port = uart_port_lock(state, flags);
648 ret = uart_circ_chars_pending(&state->xmit);
649 uart_port_unlock(port, flags);
653 static void uart_flush_buffer(struct tty_struct *tty)
655 struct uart_state *state = tty->driver_data;
656 struct uart_port *port;
660 * This means you called this function _after_ the port was
661 * closed. No cookie for you.
668 pr_debug("uart_flush_buffer(%d) called\n", tty->index);
670 port = uart_port_lock(state, flags);
673 uart_circ_clear(&state->xmit);
674 if (port->ops->flush_buffer)
675 port->ops->flush_buffer(port);
676 uart_port_unlock(port, flags);
677 tty_port_tty_wakeup(&state->port);
681 * This function performs low-level write of high-priority XON/XOFF
682 * character and accounting for it.
684 * Requires uart_port to implement .serial_out().
686 void uart_xchar_out(struct uart_port *uport, int offset)
688 serial_port_out(uport, offset, uport->x_char);
692 EXPORT_SYMBOL_GPL(uart_xchar_out);
695 * This function is used to send a high-priority XON/XOFF character to
698 static void uart_send_xchar(struct tty_struct *tty, char ch)
700 struct uart_state *state = tty->driver_data;
701 struct uart_port *port;
704 port = uart_port_ref(state);
708 if (port->ops->send_xchar)
709 port->ops->send_xchar(port, ch);
711 spin_lock_irqsave(&port->lock, flags);
714 port->ops->start_tx(port);
715 spin_unlock_irqrestore(&port->lock, flags);
717 uart_port_deref(port);
720 static void uart_throttle(struct tty_struct *tty)
722 struct uart_state *state = tty->driver_data;
723 upstat_t mask = UPSTAT_SYNC_FIFO;
724 struct uart_port *port;
726 port = uart_port_ref(state);
731 mask |= UPSTAT_AUTOXOFF;
733 mask |= UPSTAT_AUTORTS;
735 if (port->status & mask) {
736 port->ops->throttle(port);
737 mask &= ~port->status;
740 if (mask & UPSTAT_AUTORTS)
741 uart_clear_mctrl(port, TIOCM_RTS);
743 if (mask & UPSTAT_AUTOXOFF)
744 uart_send_xchar(tty, STOP_CHAR(tty));
746 uart_port_deref(port);
749 static void uart_unthrottle(struct tty_struct *tty)
751 struct uart_state *state = tty->driver_data;
752 upstat_t mask = UPSTAT_SYNC_FIFO;
753 struct uart_port *port;
755 port = uart_port_ref(state);
760 mask |= UPSTAT_AUTOXOFF;
762 mask |= UPSTAT_AUTORTS;
764 if (port->status & mask) {
765 port->ops->unthrottle(port);
766 mask &= ~port->status;
769 if (mask & UPSTAT_AUTORTS)
770 uart_set_mctrl(port, TIOCM_RTS);
772 if (mask & UPSTAT_AUTOXOFF)
773 uart_send_xchar(tty, START_CHAR(tty));
775 uart_port_deref(port);
778 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
780 struct uart_state *state = container_of(port, struct uart_state, port);
781 struct uart_port *uport;
785 * Ensure the state we copy is consistent and no hardware changes
788 mutex_lock(&port->mutex);
789 uport = uart_port_check(state);
793 retinfo->type = uport->type;
794 retinfo->line = uport->line;
795 retinfo->port = uport->iobase;
796 if (HIGH_BITS_OFFSET)
797 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
798 retinfo->irq = uport->irq;
799 retinfo->flags = (__force int)uport->flags;
800 retinfo->xmit_fifo_size = uport->fifosize;
801 retinfo->baud_base = uport->uartclk / 16;
802 retinfo->close_delay = jiffies_to_msecs(port->close_delay) / 10;
803 retinfo->closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
804 ASYNC_CLOSING_WAIT_NONE :
805 jiffies_to_msecs(port->closing_wait) / 10;
806 retinfo->custom_divisor = uport->custom_divisor;
807 retinfo->hub6 = uport->hub6;
808 retinfo->io_type = uport->iotype;
809 retinfo->iomem_reg_shift = uport->regshift;
810 retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
814 mutex_unlock(&port->mutex);
818 static int uart_get_info_user(struct tty_struct *tty,
819 struct serial_struct *ss)
821 struct uart_state *state = tty->driver_data;
822 struct tty_port *port = &state->port;
824 return uart_get_info(port, ss) < 0 ? -EIO : 0;
827 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
828 struct uart_state *state,
829 struct serial_struct *new_info)
831 struct uart_port *uport = uart_port_check(state);
832 unsigned long new_port;
833 unsigned int change_irq, change_port, closing_wait;
834 unsigned int old_custom_divisor, close_delay;
835 upf_t old_flags, new_flags;
841 new_port = new_info->port;
842 if (HIGH_BITS_OFFSET)
843 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
845 new_info->irq = irq_canonicalize(new_info->irq);
846 close_delay = msecs_to_jiffies(new_info->close_delay * 10);
847 closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
848 ASYNC_CLOSING_WAIT_NONE :
849 msecs_to_jiffies(new_info->closing_wait * 10);
852 change_irq = !(uport->flags & UPF_FIXED_PORT)
853 && new_info->irq != uport->irq;
856 * Since changing the 'type' of the port changes its resource
857 * allocations, we should treat type changes the same as
860 change_port = !(uport->flags & UPF_FIXED_PORT)
861 && (new_port != uport->iobase ||
862 (unsigned long)new_info->iomem_base != uport->mapbase ||
863 new_info->hub6 != uport->hub6 ||
864 new_info->io_type != uport->iotype ||
865 new_info->iomem_reg_shift != uport->regshift ||
866 new_info->type != uport->type);
868 old_flags = uport->flags;
869 new_flags = (__force upf_t)new_info->flags;
870 old_custom_divisor = uport->custom_divisor;
872 if (!capable(CAP_SYS_ADMIN)) {
874 if (change_irq || change_port ||
875 (new_info->baud_base != uport->uartclk / 16) ||
876 (close_delay != port->close_delay) ||
877 (closing_wait != port->closing_wait) ||
878 (new_info->xmit_fifo_size &&
879 new_info->xmit_fifo_size != uport->fifosize) ||
880 (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
882 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
883 (new_flags & UPF_USR_MASK));
884 uport->custom_divisor = new_info->custom_divisor;
888 if (change_irq || change_port) {
889 retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
895 * Ask the low level driver to verify the settings.
897 if (uport->ops->verify_port)
898 retval = uport->ops->verify_port(uport, new_info);
900 if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
901 (new_info->baud_base < 9600))
907 if (change_port || change_irq) {
911 * Make sure that we are the sole user of this port.
913 if (tty_port_users(port) > 1)
917 * We need to shutdown the serial port at the old
918 * port/type/irq combination.
920 uart_shutdown(tty, state);
924 unsigned long old_iobase, old_mapbase;
925 unsigned int old_type, old_iotype, old_hub6, old_shift;
927 old_iobase = uport->iobase;
928 old_mapbase = uport->mapbase;
929 old_type = uport->type;
930 old_hub6 = uport->hub6;
931 old_iotype = uport->iotype;
932 old_shift = uport->regshift;
935 * Free and release old regions
937 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
938 uport->ops->release_port(uport);
940 uport->iobase = new_port;
941 uport->type = new_info->type;
942 uport->hub6 = new_info->hub6;
943 uport->iotype = new_info->io_type;
944 uport->regshift = new_info->iomem_reg_shift;
945 uport->mapbase = (unsigned long)new_info->iomem_base;
948 * Claim and map the new regions
950 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
951 retval = uport->ops->request_port(uport);
953 /* Always success - Jean II */
958 * If we fail to request resources for the
959 * new port, try to restore the old settings.
962 uport->iobase = old_iobase;
963 uport->type = old_type;
964 uport->hub6 = old_hub6;
965 uport->iotype = old_iotype;
966 uport->regshift = old_shift;
967 uport->mapbase = old_mapbase;
969 if (old_type != PORT_UNKNOWN) {
970 retval = uport->ops->request_port(uport);
972 * If we failed to restore the old settings,
976 uport->type = PORT_UNKNOWN;
984 /* Added to return the correct error -Ram Gupta */
990 uport->irq = new_info->irq;
991 if (!(uport->flags & UPF_FIXED_PORT))
992 uport->uartclk = new_info->baud_base * 16;
993 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
994 (new_flags & UPF_CHANGE_MASK);
995 uport->custom_divisor = new_info->custom_divisor;
996 port->close_delay = close_delay;
997 port->closing_wait = closing_wait;
998 if (new_info->xmit_fifo_size)
999 uport->fifosize = new_info->xmit_fifo_size;
1003 if (uport->type == PORT_UNKNOWN)
1005 if (tty_port_initialized(port)) {
1006 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
1007 old_custom_divisor != uport->custom_divisor) {
1009 * If they're setting up a custom divisor or speed,
1010 * instead of clearing it, then bitch about it.
1012 if (uport->flags & UPF_SPD_MASK) {
1013 dev_notice_ratelimited(uport->dev,
1014 "%s sets custom speed on %s. This is deprecated.\n",
1016 tty_name(port->tty));
1018 uart_change_line_settings(tty, state, NULL);
1021 retval = uart_startup(tty, state, true);
1023 tty_port_set_initialized(port, true);
1031 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1033 struct uart_state *state = tty->driver_data;
1034 struct tty_port *port = &state->port;
1037 down_write(&tty->termios_rwsem);
1039 * This semaphore protects port->count. It is also
1040 * very useful to prevent opens. Also, take the
1041 * port configuration semaphore to make sure that a
1042 * module insertion/removal doesn't change anything
1045 mutex_lock(&port->mutex);
1046 retval = uart_set_info(tty, port, state, ss);
1047 mutex_unlock(&port->mutex);
1048 up_write(&tty->termios_rwsem);
1053 * uart_get_lsr_info - get line status register info
1054 * @tty: tty associated with the UART
1055 * @state: UART being queried
1056 * @value: returned modem value
1058 static int uart_get_lsr_info(struct tty_struct *tty,
1059 struct uart_state *state, unsigned int __user *value)
1061 struct uart_port *uport = uart_port_check(state);
1062 unsigned int result;
1064 result = uport->ops->tx_empty(uport);
1067 * If we're about to load something into the transmit
1068 * register, we'll pretend the transmitter isn't empty to
1069 * avoid a race condition (depending on when the transmit
1070 * interrupt happens).
1072 if (uport->x_char ||
1073 ((uart_circ_chars_pending(&state->xmit) > 0) &&
1074 !uart_tx_stopped(uport)))
1075 result &= ~TIOCSER_TEMT;
1077 return put_user(result, value);
1080 static int uart_tiocmget(struct tty_struct *tty)
1082 struct uart_state *state = tty->driver_data;
1083 struct tty_port *port = &state->port;
1084 struct uart_port *uport;
1087 mutex_lock(&port->mutex);
1088 uport = uart_port_check(state);
1092 if (!tty_io_error(tty)) {
1093 result = uport->mctrl;
1094 spin_lock_irq(&uport->lock);
1095 result |= uport->ops->get_mctrl(uport);
1096 spin_unlock_irq(&uport->lock);
1099 mutex_unlock(&port->mutex);
1104 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1106 struct uart_state *state = tty->driver_data;
1107 struct tty_port *port = &state->port;
1108 struct uart_port *uport;
1111 mutex_lock(&port->mutex);
1112 uport = uart_port_check(state);
1116 if (!tty_io_error(tty)) {
1117 uart_update_mctrl(uport, set, clear);
1121 mutex_unlock(&port->mutex);
1125 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1127 struct uart_state *state = tty->driver_data;
1128 struct tty_port *port = &state->port;
1129 struct uart_port *uport;
1132 mutex_lock(&port->mutex);
1133 uport = uart_port_check(state);
1137 if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1138 uport->ops->break_ctl(uport, break_state);
1141 mutex_unlock(&port->mutex);
1145 static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1147 struct tty_port *port = &state->port;
1148 struct uart_port *uport;
1151 if (!capable(CAP_SYS_ADMIN))
1155 * Take the per-port semaphore. This prevents count from
1156 * changing, and hence any extra opens of the port while
1157 * we're auto-configuring.
1159 if (mutex_lock_interruptible(&port->mutex))
1160 return -ERESTARTSYS;
1162 uport = uart_port_check(state);
1169 if (tty_port_users(port) == 1) {
1170 uart_shutdown(tty, state);
1173 * If we already have a port type configured,
1174 * we must release its resources.
1176 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1177 uport->ops->release_port(uport);
1179 flags = UART_CONFIG_TYPE;
1180 if (uport->flags & UPF_AUTO_IRQ)
1181 flags |= UART_CONFIG_IRQ;
1184 * This will claim the ports resources if
1187 uport->ops->config_port(uport, flags);
1189 ret = uart_startup(tty, state, true);
1191 tty_port_set_initialized(port, true);
1196 mutex_unlock(&port->mutex);
1200 static void uart_enable_ms(struct uart_port *uport)
1203 * Force modem status interrupts on
1205 if (uport->ops->enable_ms)
1206 uport->ops->enable_ms(uport);
1210 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1211 * - mask passed in arg for lines of interest
1212 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1213 * Caller should use TIOCGICOUNT to see which one it was
1215 * FIXME: This wants extracting into a common all driver implementation
1216 * of TIOCMWAIT using tty_port.
1218 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1220 struct uart_port *uport;
1221 struct tty_port *port = &state->port;
1222 DECLARE_WAITQUEUE(wait, current);
1223 struct uart_icount cprev, cnow;
1227 * note the counters on entry
1229 uport = uart_port_ref(state);
1232 spin_lock_irq(&uport->lock);
1233 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1234 uart_enable_ms(uport);
1235 spin_unlock_irq(&uport->lock);
1237 add_wait_queue(&port->delta_msr_wait, &wait);
1239 spin_lock_irq(&uport->lock);
1240 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1241 spin_unlock_irq(&uport->lock);
1243 set_current_state(TASK_INTERRUPTIBLE);
1245 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1246 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1247 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1248 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1255 /* see if a signal did it */
1256 if (signal_pending(current)) {
1263 __set_current_state(TASK_RUNNING);
1264 remove_wait_queue(&port->delta_msr_wait, &wait);
1265 uart_port_deref(uport);
1271 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1272 * Return: write counters to the user passed counter struct
1273 * NB: both 1->0 and 0->1 transitions are counted except for
1274 * RI where only 0->1 is counted.
1276 static int uart_get_icount(struct tty_struct *tty,
1277 struct serial_icounter_struct *icount)
1279 struct uart_state *state = tty->driver_data;
1280 struct uart_icount cnow;
1281 struct uart_port *uport;
1283 uport = uart_port_ref(state);
1286 spin_lock_irq(&uport->lock);
1287 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1288 spin_unlock_irq(&uport->lock);
1289 uart_port_deref(uport);
1291 icount->cts = cnow.cts;
1292 icount->dsr = cnow.dsr;
1293 icount->rng = cnow.rng;
1294 icount->dcd = cnow.dcd;
1295 icount->rx = cnow.rx;
1296 icount->tx = cnow.tx;
1297 icount->frame = cnow.frame;
1298 icount->overrun = cnow.overrun;
1299 icount->parity = cnow.parity;
1300 icount->brk = cnow.brk;
1301 icount->buf_overrun = cnow.buf_overrun;
1306 #define SER_RS485_LEGACY_FLAGS (SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
1307 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
1308 SER_RS485_TERMINATE_BUS)
1310 static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
1312 u32 flags = rs485->flags;
1314 /* Don't return -EINVAL for unsupported legacy flags */
1315 flags &= ~SER_RS485_LEGACY_FLAGS;
1318 * For any bit outside of the legacy ones that is not supported by
1319 * the driver, return -EINVAL.
1321 if (flags & ~port->rs485_supported.flags)
1324 /* Asking for address w/o addressing mode? */
1325 if (!(rs485->flags & SER_RS485_ADDRB) &&
1326 (rs485->flags & (SER_RS485_ADDR_RECV|SER_RS485_ADDR_DEST)))
1329 /* Address given but not enabled? */
1330 if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv)
1332 if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest)
1338 static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
1339 struct serial_rs485 *rs485)
1341 if (!port->rs485_supported.delay_rts_before_send) {
1342 if (rs485->delay_rts_before_send) {
1343 dev_warn_ratelimited(port->dev,
1344 "%s (%d): RTS delay before sending not supported\n",
1345 port->name, port->line);
1347 rs485->delay_rts_before_send = 0;
1348 } else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) {
1349 rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY;
1350 dev_warn_ratelimited(port->dev,
1351 "%s (%d): RTS delay before sending clamped to %u ms\n",
1352 port->name, port->line, rs485->delay_rts_before_send);
1355 if (!port->rs485_supported.delay_rts_after_send) {
1356 if (rs485->delay_rts_after_send) {
1357 dev_warn_ratelimited(port->dev,
1358 "%s (%d): RTS delay after sending not supported\n",
1359 port->name, port->line);
1361 rs485->delay_rts_after_send = 0;
1362 } else if (rs485->delay_rts_after_send > RS485_MAX_RTS_DELAY) {
1363 rs485->delay_rts_after_send = RS485_MAX_RTS_DELAY;
1364 dev_warn_ratelimited(port->dev,
1365 "%s (%d): RTS delay after sending clamped to %u ms\n",
1366 port->name, port->line, rs485->delay_rts_after_send);
1370 static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485)
1372 u32 supported_flags = port->rs485_supported.flags;
1374 if (!(rs485->flags & SER_RS485_ENABLED)) {
1375 memset(rs485, 0, sizeof(*rs485));
1379 /* Pick sane settings if the user hasn't */
1380 if ((supported_flags & (SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND)) &&
1381 !(rs485->flags & SER_RS485_RTS_ON_SEND) ==
1382 !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
1383 dev_warn_ratelimited(port->dev,
1384 "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
1385 port->name, port->line);
1386 rs485->flags |= SER_RS485_RTS_ON_SEND;
1387 rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
1388 supported_flags |= SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND;
1391 rs485->flags &= supported_flags;
1393 uart_sanitize_serial_rs485_delays(port, rs485);
1395 /* Return clean padding area to userspace */
1396 memset(rs485->padding0, 0, sizeof(rs485->padding0));
1397 memset(rs485->padding1, 0, sizeof(rs485->padding1));
1400 static void uart_set_rs485_termination(struct uart_port *port,
1401 const struct serial_rs485 *rs485)
1403 if (!(rs485->flags & SER_RS485_ENABLED))
1406 gpiod_set_value_cansleep(port->rs485_term_gpio,
1407 !!(rs485->flags & SER_RS485_TERMINATE_BUS));
1410 static int uart_rs485_config(struct uart_port *port)
1412 struct serial_rs485 *rs485 = &port->rs485;
1415 uart_sanitize_serial_rs485(port, rs485);
1416 uart_set_rs485_termination(port, rs485);
1418 ret = port->rs485_config(port, NULL, rs485);
1420 memset(rs485, 0, sizeof(*rs485));
1425 static int uart_get_rs485_config(struct uart_port *port,
1426 struct serial_rs485 __user *rs485)
1428 unsigned long flags;
1429 struct serial_rs485 aux;
1431 spin_lock_irqsave(&port->lock, flags);
1433 spin_unlock_irqrestore(&port->lock, flags);
1435 if (copy_to_user(rs485, &aux, sizeof(aux)))
1441 static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
1442 struct serial_rs485 __user *rs485_user)
1444 struct serial_rs485 rs485;
1446 unsigned long flags;
1448 if (!port->rs485_config)
1451 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1454 ret = uart_check_rs485_flags(port, &rs485);
1457 uart_sanitize_serial_rs485(port, &rs485);
1458 uart_set_rs485_termination(port, &rs485);
1460 spin_lock_irqsave(&port->lock, flags);
1461 ret = port->rs485_config(port, &tty->termios, &rs485);
1463 port->rs485 = rs485;
1465 /* Reset RTS and other mctrl lines when disabling RS485 */
1466 if (!(rs485.flags & SER_RS485_ENABLED))
1467 port->ops->set_mctrl(port, port->mctrl);
1469 spin_unlock_irqrestore(&port->lock, flags);
1473 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1479 static int uart_get_iso7816_config(struct uart_port *port,
1480 struct serial_iso7816 __user *iso7816)
1482 unsigned long flags;
1483 struct serial_iso7816 aux;
1485 if (!port->iso7816_config)
1488 spin_lock_irqsave(&port->lock, flags);
1489 aux = port->iso7816;
1490 spin_unlock_irqrestore(&port->lock, flags);
1492 if (copy_to_user(iso7816, &aux, sizeof(aux)))
1498 static int uart_set_iso7816_config(struct uart_port *port,
1499 struct serial_iso7816 __user *iso7816_user)
1501 struct serial_iso7816 iso7816;
1503 unsigned long flags;
1505 if (!port->iso7816_config)
1508 if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1512 * There are 5 words reserved for future use. Check that userspace
1513 * doesn't put stuff in there to prevent breakages in the future.
1515 for (i = 0; i < ARRAY_SIZE(iso7816.reserved); i++)
1516 if (iso7816.reserved[i])
1519 spin_lock_irqsave(&port->lock, flags);
1520 ret = port->iso7816_config(port, &iso7816);
1521 spin_unlock_irqrestore(&port->lock, flags);
1525 if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1532 * Called via sys_ioctl. We can use spin_lock_irq() here.
1535 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1537 struct uart_state *state = tty->driver_data;
1538 struct tty_port *port = &state->port;
1539 struct uart_port *uport;
1540 void __user *uarg = (void __user *)arg;
1541 int ret = -ENOIOCTLCMD;
1545 * These ioctls don't rely on the hardware to be present.
1549 down_write(&tty->termios_rwsem);
1550 ret = uart_do_autoconfig(tty, state);
1551 up_write(&tty->termios_rwsem);
1555 if (ret != -ENOIOCTLCMD)
1558 if (tty_io_error(tty)) {
1564 * The following should only be used when hardware is present.
1568 ret = uart_wait_modem_status(state, arg);
1572 if (ret != -ENOIOCTLCMD)
1575 /* rs485_config requires more locking than others */
1576 if (cmd == TIOCSRS485)
1577 down_write(&tty->termios_rwsem);
1579 mutex_lock(&port->mutex);
1580 uport = uart_port_check(state);
1582 if (!uport || tty_io_error(tty)) {
1588 * All these rely on hardware being present and need to be
1589 * protected against the tty being hung up.
1593 case TIOCSERGETLSR: /* Get line status register */
1594 ret = uart_get_lsr_info(tty, state, uarg);
1598 ret = uart_get_rs485_config(uport, uarg);
1602 ret = uart_set_rs485_config(tty, uport, uarg);
1606 ret = uart_set_iso7816_config(state->uart_port, uarg);
1610 ret = uart_get_iso7816_config(state->uart_port, uarg);
1613 if (uport->ops->ioctl)
1614 ret = uport->ops->ioctl(uport, cmd, arg);
1618 mutex_unlock(&port->mutex);
1619 if (cmd == TIOCSRS485)
1620 up_write(&tty->termios_rwsem);
1625 static void uart_set_ldisc(struct tty_struct *tty)
1627 struct uart_state *state = tty->driver_data;
1628 struct uart_port *uport;
1629 struct tty_port *port = &state->port;
1631 if (!tty_port_initialized(port))
1634 mutex_lock(&state->port.mutex);
1635 uport = uart_port_check(state);
1636 if (uport && uport->ops->set_ldisc)
1637 uport->ops->set_ldisc(uport, &tty->termios);
1638 mutex_unlock(&state->port.mutex);
1641 static void uart_set_termios(struct tty_struct *tty,
1642 const struct ktermios *old_termios)
1644 struct uart_state *state = tty->driver_data;
1645 struct uart_port *uport;
1646 unsigned int cflag = tty->termios.c_cflag;
1647 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1648 bool sw_changed = false;
1650 mutex_lock(&state->port.mutex);
1651 uport = uart_port_check(state);
1656 * Drivers doing software flow control also need to know
1657 * about changes to these input settings.
1659 if (uport->flags & UPF_SOFT_FLOW) {
1660 iflag_mask |= IXANY|IXON|IXOFF;
1662 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1663 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1667 * These are the bits that are used to setup various
1668 * flags in the low level driver. We can ignore the Bfoo
1669 * bits in c_cflag; c_[io]speed will always be set
1670 * appropriately by set_termios() in tty_ioctl.c
1672 if ((cflag ^ old_termios->c_cflag) == 0 &&
1673 tty->termios.c_ospeed == old_termios->c_ospeed &&
1674 tty->termios.c_ispeed == old_termios->c_ispeed &&
1675 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1680 uart_change_line_settings(tty, state, old_termios);
1681 /* reload cflag from termios; port driver may have overridden flags */
1682 cflag = tty->termios.c_cflag;
1684 /* Handle transition to B0 status */
1685 if (((old_termios->c_cflag & CBAUD) != B0) && ((cflag & CBAUD) == B0))
1686 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1687 /* Handle transition away from B0 status */
1688 else if (((old_termios->c_cflag & CBAUD) == B0) && ((cflag & CBAUD) != B0)) {
1689 unsigned int mask = TIOCM_DTR;
1691 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1693 uart_set_mctrl(uport, mask);
1696 mutex_unlock(&state->port.mutex);
1700 * Calls to uart_close() are serialised via the tty_lock in
1701 * drivers/tty/tty_io.c:tty_release()
1702 * drivers/tty/tty_io.c:do_tty_hangup()
1704 static void uart_close(struct tty_struct *tty, struct file *filp)
1706 struct uart_state *state = tty->driver_data;
1709 struct uart_driver *drv = tty->driver->driver_state;
1710 struct tty_port *port;
1712 state = drv->state + tty->index;
1713 port = &state->port;
1714 spin_lock_irq(&port->lock);
1716 spin_unlock_irq(&port->lock);
1720 pr_debug("uart_close(%d) called\n", tty->index);
1722 tty_port_close(tty->port, tty, filp);
1725 static void uart_tty_port_shutdown(struct tty_port *port)
1727 struct uart_state *state = container_of(port, struct uart_state, port);
1728 struct uart_port *uport = uart_port_check(state);
1732 * At this point, we stop accepting input. To do this, we
1733 * disable the receive line status interrupts.
1735 if (WARN(!uport, "detached port still initialized!\n"))
1738 spin_lock_irq(&uport->lock);
1739 uport->ops->stop_rx(uport);
1740 spin_unlock_irq(&uport->lock);
1742 uart_port_shutdown(port);
1745 * It's possible for shutdown to be called after suspend if we get
1746 * a DCD drop (hangup) at just the right time. Clear suspended bit so
1747 * we don't try to resume a port that has been shutdown.
1749 tty_port_set_suspended(port, false);
1752 * Free the transmit buffer.
1754 spin_lock_irq(&uport->lock);
1755 buf = state->xmit.buf;
1756 state->xmit.buf = NULL;
1757 spin_unlock_irq(&uport->lock);
1759 free_page((unsigned long)buf);
1761 uart_change_pm(state, UART_PM_STATE_OFF);
1764 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1766 struct uart_state *state = tty->driver_data;
1767 struct uart_port *port;
1768 unsigned long char_time, expire, fifo_timeout;
1770 port = uart_port_ref(state);
1774 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1775 uart_port_deref(port);
1780 * Set the check interval to be 1/5 of the estimated time to
1781 * send a single character, and make it at least 1. The check
1782 * interval should also be less than the timeout.
1784 * Note: we have to use pretty tight timings here to satisfy
1787 char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
1789 if (timeout && timeout < char_time)
1790 char_time = timeout;
1792 if (!uart_cts_enabled(port)) {
1794 * If the transmitter hasn't cleared in twice the approximate
1795 * amount of time to send the entire FIFO, it probably won't
1796 * ever clear. This assumes the UART isn't doing flow
1797 * control, which is currently the case. Hence, if it ever
1798 * takes longer than FIFO timeout, this is probably due to a
1799 * UART bug of some kind. So, we clamp the timeout parameter at
1802 fifo_timeout = uart_fifo_timeout(port);
1803 if (timeout == 0 || timeout > 2 * fifo_timeout)
1804 timeout = 2 * fifo_timeout;
1807 expire = jiffies + timeout;
1809 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1810 port->line, jiffies, expire);
1813 * Check whether the transmitter is empty every 'char_time'.
1814 * 'timeout' / 'expire' give us the maximum amount of time
1817 while (!port->ops->tx_empty(port)) {
1818 msleep_interruptible(jiffies_to_msecs(char_time));
1819 if (signal_pending(current))
1821 if (timeout && time_after(jiffies, expire))
1824 uart_port_deref(port);
1828 * Calls to uart_hangup() are serialised by the tty_lock in
1829 * drivers/tty/tty_io.c:do_tty_hangup()
1830 * This runs from a workqueue and can sleep for a _short_ time only.
1832 static void uart_hangup(struct tty_struct *tty)
1834 struct uart_state *state = tty->driver_data;
1835 struct tty_port *port = &state->port;
1836 struct uart_port *uport;
1837 unsigned long flags;
1839 pr_debug("uart_hangup(%d)\n", tty->index);
1841 mutex_lock(&port->mutex);
1842 uport = uart_port_check(state);
1843 WARN(!uport, "hangup of detached port!\n");
1845 if (tty_port_active(port)) {
1846 uart_flush_buffer(tty);
1847 uart_shutdown(tty, state);
1848 spin_lock_irqsave(&port->lock, flags);
1850 spin_unlock_irqrestore(&port->lock, flags);
1851 tty_port_set_active(port, false);
1852 tty_port_tty_set(port, NULL);
1853 if (uport && !uart_console(uport))
1854 uart_change_pm(state, UART_PM_STATE_OFF);
1855 wake_up_interruptible(&port->open_wait);
1856 wake_up_interruptible(&port->delta_msr_wait);
1858 mutex_unlock(&port->mutex);
1861 /* uport == NULL if uart_port has already been removed */
1862 static void uart_port_shutdown(struct tty_port *port)
1864 struct uart_state *state = container_of(port, struct uart_state, port);
1865 struct uart_port *uport = uart_port_check(state);
1868 * clear delta_msr_wait queue to avoid mem leaks: we may free
1869 * the irq here so the queue might never be woken up. Note
1870 * that we won't end up waiting on delta_msr_wait again since
1871 * any outstanding file descriptors should be pointing at
1872 * hung_up_tty_fops now.
1874 wake_up_interruptible(&port->delta_msr_wait);
1877 /* Free the IRQ and disable the port. */
1878 uport->ops->shutdown(uport);
1880 /* Ensure that the IRQ handler isn't running on another CPU. */
1881 synchronize_irq(uport->irq);
1885 static bool uart_carrier_raised(struct tty_port *port)
1887 struct uart_state *state = container_of(port, struct uart_state, port);
1888 struct uart_port *uport;
1891 uport = uart_port_ref(state);
1893 * Should never observe uport == NULL since checks for hangup should
1894 * abort the tty_port_block_til_ready() loop before checking for carrier
1895 * raised -- but report carrier raised if it does anyway so open will
1896 * continue and not sleep
1898 if (WARN_ON(!uport))
1900 spin_lock_irq(&uport->lock);
1901 uart_enable_ms(uport);
1902 mctrl = uport->ops->get_mctrl(uport);
1903 spin_unlock_irq(&uport->lock);
1904 uart_port_deref(uport);
1906 return mctrl & TIOCM_CAR;
1909 static void uart_dtr_rts(struct tty_port *port, bool active)
1911 struct uart_state *state = container_of(port, struct uart_state, port);
1912 struct uart_port *uport;
1914 uport = uart_port_ref(state);
1917 uart_port_dtr_rts(uport, active);
1918 uart_port_deref(uport);
1921 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1923 struct uart_driver *drv = driver->driver_state;
1924 struct uart_state *state = drv->state + tty->index;
1926 tty->driver_data = state;
1928 return tty_standard_install(driver, tty);
1932 * Calls to uart_open are serialised by the tty_lock in
1933 * drivers/tty/tty_io.c:tty_open()
1934 * Note that if this fails, then uart_close() _will_ be called.
1936 * In time, we want to scrap the "opening nonpresent ports"
1937 * behaviour and implement an alternative way for setserial
1938 * to set base addresses/ports/types. This will allow us to
1939 * get rid of a certain amount of extra tests.
1941 static int uart_open(struct tty_struct *tty, struct file *filp)
1943 struct uart_state *state = tty->driver_data;
1946 retval = tty_port_open(&state->port, tty, filp);
1953 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1955 struct uart_state *state = container_of(port, struct uart_state, port);
1956 struct uart_port *uport;
1959 uport = uart_port_check(state);
1960 if (!uport || uport->flags & UPF_DEAD)
1964 * Start up the serial port.
1966 ret = uart_startup(tty, state, false);
1968 tty_port_set_active(port, true);
1973 static const char *uart_type(struct uart_port *port)
1975 const char *str = NULL;
1977 if (port->ops->type)
1978 str = port->ops->type(port);
1986 #ifdef CONFIG_PROC_FS
1988 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1990 struct uart_state *state = drv->state + i;
1991 struct tty_port *port = &state->port;
1992 enum uart_pm_state pm_state;
1993 struct uart_port *uport;
1995 unsigned int status;
1998 mutex_lock(&port->mutex);
1999 uport = uart_port_check(state);
2003 mmio = uport->iotype >= UPIO_MEM;
2004 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
2005 uport->line, uart_type(uport),
2006 mmio ? "mmio:0x" : "port:",
2007 mmio ? (unsigned long long)uport->mapbase
2008 : (unsigned long long)uport->iobase,
2011 if (uport->type == PORT_UNKNOWN) {
2016 if (capable(CAP_SYS_ADMIN)) {
2017 pm_state = state->pm_state;
2018 if (pm_state != UART_PM_STATE_ON)
2019 uart_change_pm(state, UART_PM_STATE_ON);
2020 spin_lock_irq(&uport->lock);
2021 status = uport->ops->get_mctrl(uport);
2022 spin_unlock_irq(&uport->lock);
2023 if (pm_state != UART_PM_STATE_ON)
2024 uart_change_pm(state, pm_state);
2026 seq_printf(m, " tx:%d rx:%d",
2027 uport->icount.tx, uport->icount.rx);
2028 if (uport->icount.frame)
2029 seq_printf(m, " fe:%d", uport->icount.frame);
2030 if (uport->icount.parity)
2031 seq_printf(m, " pe:%d", uport->icount.parity);
2032 if (uport->icount.brk)
2033 seq_printf(m, " brk:%d", uport->icount.brk);
2034 if (uport->icount.overrun)
2035 seq_printf(m, " oe:%d", uport->icount.overrun);
2036 if (uport->icount.buf_overrun)
2037 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
2039 #define INFOBIT(bit, str) \
2040 if (uport->mctrl & (bit)) \
2041 strncat(stat_buf, (str), sizeof(stat_buf) - \
2042 strlen(stat_buf) - 2)
2043 #define STATBIT(bit, str) \
2044 if (status & (bit)) \
2045 strncat(stat_buf, (str), sizeof(stat_buf) - \
2046 strlen(stat_buf) - 2)
2050 INFOBIT(TIOCM_RTS, "|RTS");
2051 STATBIT(TIOCM_CTS, "|CTS");
2052 INFOBIT(TIOCM_DTR, "|DTR");
2053 STATBIT(TIOCM_DSR, "|DSR");
2054 STATBIT(TIOCM_CAR, "|CD");
2055 STATBIT(TIOCM_RNG, "|RI");
2059 seq_puts(m, stat_buf);
2065 mutex_unlock(&port->mutex);
2068 static int uart_proc_show(struct seq_file *m, void *v)
2070 struct tty_driver *ttydrv = m->private;
2071 struct uart_driver *drv = ttydrv->driver_state;
2074 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
2075 for (i = 0; i < drv->nr; i++)
2076 uart_line_info(m, drv, i);
2081 static void uart_port_spin_lock_init(struct uart_port *port)
2083 spin_lock_init(&port->lock);
2084 lockdep_set_class(&port->lock, &port_lock_key);
2087 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
2089 * uart_console_write - write a console message to a serial port
2090 * @port: the port to write the message
2091 * @s: array of characters
2092 * @count: number of characters in string to write
2093 * @putchar: function to write character to port
2095 void uart_console_write(struct uart_port *port, const char *s,
2097 void (*putchar)(struct uart_port *, unsigned char))
2101 for (i = 0; i < count; i++, s++) {
2103 putchar(port, '\r');
2107 EXPORT_SYMBOL_GPL(uart_console_write);
2110 * uart_get_console - get uart port for console
2111 * @ports: ports to search in
2112 * @nr: number of @ports
2113 * @co: console to search for
2114 * Returns: uart_port for the console @co
2116 * Check whether an invalid uart number has been specified (as @co->index), and
2117 * if so, search for the first available port that does have console support.
2119 struct uart_port * __init
2120 uart_get_console(struct uart_port *ports, int nr, struct console *co)
2122 int idx = co->index;
2124 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
2125 ports[idx].membase == NULL))
2126 for (idx = 0; idx < nr; idx++)
2127 if (ports[idx].iobase != 0 ||
2128 ports[idx].membase != NULL)
2137 * uart_parse_earlycon - Parse earlycon options
2138 * @p: ptr to 2nd field (ie., just beyond '<name>,')
2139 * @iotype: ptr for decoded iotype (out)
2140 * @addr: ptr for decoded mapbase/iobase (out)
2141 * @options: ptr for <options> field; %NULL if not present (out)
2143 * Decodes earlycon kernel command line parameters of the form:
2144 * * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2145 * * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2147 * The optional form:
2148 * * earlycon=<name>,0x<addr>,<options>
2149 * * console=<name>,0x<addr>,<options>
2151 * is also accepted; the returned @iotype will be %UPIO_MEM.
2153 * Returns: 0 on success or -%EINVAL on failure
2155 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
2158 if (strncmp(p, "mmio,", 5) == 0) {
2161 } else if (strncmp(p, "mmio16,", 7) == 0) {
2162 *iotype = UPIO_MEM16;
2164 } else if (strncmp(p, "mmio32,", 7) == 0) {
2165 *iotype = UPIO_MEM32;
2167 } else if (strncmp(p, "mmio32be,", 9) == 0) {
2168 *iotype = UPIO_MEM32BE;
2170 } else if (strncmp(p, "mmio32native,", 13) == 0) {
2171 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2172 UPIO_MEM32BE : UPIO_MEM32;
2174 } else if (strncmp(p, "io,", 3) == 0) {
2175 *iotype = UPIO_PORT;
2177 } else if (strncmp(p, "0x", 2) == 0) {
2184 * Before you replace it with kstrtoull(), think about options separator
2185 * (',') it will not tolerate
2187 *addr = simple_strtoull(p, NULL, 0);
2195 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2198 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2199 * @options: pointer to option string
2200 * @baud: pointer to an 'int' variable for the baud rate.
2201 * @parity: pointer to an 'int' variable for the parity.
2202 * @bits: pointer to an 'int' variable for the number of data bits.
2203 * @flow: pointer to an 'int' variable for the flow control character.
2205 * uart_parse_options() decodes a string containing the serial console
2206 * options. The format of the string is <baud><parity><bits><flow>,
2210 uart_parse_options(const char *options, int *baud, int *parity,
2211 int *bits, int *flow)
2213 const char *s = options;
2215 *baud = simple_strtoul(s, NULL, 10);
2216 while (*s >= '0' && *s <= '9')
2225 EXPORT_SYMBOL_GPL(uart_parse_options);
2228 * uart_set_options - setup the serial console parameters
2229 * @port: pointer to the serial ports uart_port structure
2230 * @co: console pointer
2232 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2233 * @bits: number of data bits
2234 * @flow: flow control character - 'r' (rts)
2236 * Locking: Caller must hold console_list_lock in order to serialize
2237 * early initialization of the serial-console lock.
2240 uart_set_options(struct uart_port *port, struct console *co,
2241 int baud, int parity, int bits, int flow)
2243 struct ktermios termios;
2244 static struct ktermios dummy;
2247 * Ensure that the serial-console lock is initialised early.
2249 * Note that the console-registered check is needed because
2250 * kgdboc can call uart_set_options() for an already registered
2251 * console via tty_find_polling_driver() and uart_poll_init().
2253 if (!uart_console_registered_locked(port) && !port->console_reinit)
2254 uart_port_spin_lock_init(port);
2256 memset(&termios, 0, sizeof(struct ktermios));
2258 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2259 tty_termios_encode_baud_rate(&termios, baud, baud);
2262 termios.c_cflag |= CS7;
2264 termios.c_cflag |= CS8;
2268 termios.c_cflag |= PARODD;
2271 termios.c_cflag |= PARENB;
2276 termios.c_cflag |= CRTSCTS;
2279 * some uarts on other side don't support no flow control.
2280 * So we set * DTR in host uart to make them happy
2282 port->mctrl |= TIOCM_DTR;
2284 port->ops->set_termios(port, &termios, &dummy);
2286 * Allow the setting of the UART parameters with a NULL console
2290 co->cflag = termios.c_cflag;
2291 co->ispeed = termios.c_ispeed;
2292 co->ospeed = termios.c_ospeed;
2297 EXPORT_SYMBOL_GPL(uart_set_options);
2298 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2301 * uart_change_pm - set power state of the port
2303 * @state: port descriptor
2304 * @pm_state: new state
2306 * Locking: port->mutex has to be held
2308 static void uart_change_pm(struct uart_state *state,
2309 enum uart_pm_state pm_state)
2311 struct uart_port *port = uart_port_check(state);
2313 if (state->pm_state != pm_state) {
2314 if (port && port->ops->pm)
2315 port->ops->pm(port, pm_state, state->pm_state);
2316 state->pm_state = pm_state;
2321 struct uart_port *port;
2322 struct uart_driver *driver;
2325 static int serial_match_port(struct device *dev, void *data)
2327 struct uart_match *match = data;
2328 struct tty_driver *tty_drv = match->driver->tty_driver;
2329 dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2332 return dev->devt == devt; /* Actually, only one tty per port */
2335 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2337 struct uart_state *state = drv->state + uport->line;
2338 struct tty_port *port = &state->port;
2339 struct device *tty_dev;
2340 struct uart_match match = {uport, drv};
2342 mutex_lock(&port->mutex);
2344 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2345 if (tty_dev && device_may_wakeup(tty_dev)) {
2346 enable_irq_wake(uport->irq);
2347 put_device(tty_dev);
2348 mutex_unlock(&port->mutex);
2351 put_device(tty_dev);
2354 * Nothing to do if the console is not suspending
2355 * except stop_rx to prevent any asynchronous data
2356 * over RX line. However ensure that we will be
2357 * able to Re-start_rx later.
2359 if (!console_suspend_enabled && uart_console(uport)) {
2360 if (uport->ops->start_rx) {
2361 spin_lock_irq(&uport->lock);
2362 uport->ops->stop_rx(uport);
2363 spin_unlock_irq(&uport->lock);
2368 uport->suspended = 1;
2370 if (tty_port_initialized(port)) {
2371 const struct uart_ops *ops = uport->ops;
2375 tty_port_set_suspended(port, true);
2376 tty_port_set_initialized(port, false);
2378 spin_lock_irq(&uport->lock);
2379 ops->stop_tx(uport);
2380 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2381 ops->set_mctrl(uport, 0);
2382 /* save mctrl so it can be restored on resume */
2383 mctrl = uport->mctrl;
2385 ops->stop_rx(uport);
2386 spin_unlock_irq(&uport->lock);
2389 * Wait for the transmitter to empty.
2391 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2394 dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2397 ops->shutdown(uport);
2398 uport->mctrl = mctrl;
2402 * Disable the console device before suspending.
2404 if (uart_console(uport))
2405 console_stop(uport->cons);
2407 uart_change_pm(state, UART_PM_STATE_OFF);
2409 mutex_unlock(&port->mutex);
2413 EXPORT_SYMBOL(uart_suspend_port);
2415 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2417 struct uart_state *state = drv->state + uport->line;
2418 struct tty_port *port = &state->port;
2419 struct device *tty_dev;
2420 struct uart_match match = {uport, drv};
2421 struct ktermios termios;
2423 mutex_lock(&port->mutex);
2425 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2426 if (!uport->suspended && device_may_wakeup(tty_dev)) {
2427 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2428 disable_irq_wake(uport->irq);
2429 put_device(tty_dev);
2430 mutex_unlock(&port->mutex);
2433 put_device(tty_dev);
2434 uport->suspended = 0;
2437 * Re-enable the console device after suspending.
2439 if (uart_console(uport)) {
2441 * First try to use the console cflag setting.
2443 memset(&termios, 0, sizeof(struct ktermios));
2444 termios.c_cflag = uport->cons->cflag;
2445 termios.c_ispeed = uport->cons->ispeed;
2446 termios.c_ospeed = uport->cons->ospeed;
2449 * If that's unset, use the tty termios setting.
2451 if (port->tty && termios.c_cflag == 0)
2452 termios = port->tty->termios;
2454 if (console_suspend_enabled)
2455 uart_change_pm(state, UART_PM_STATE_ON);
2456 uport->ops->set_termios(uport, &termios, NULL);
2457 if (!console_suspend_enabled && uport->ops->start_rx) {
2458 spin_lock_irq(&uport->lock);
2459 uport->ops->start_rx(uport);
2460 spin_unlock_irq(&uport->lock);
2462 if (console_suspend_enabled)
2463 console_start(uport->cons);
2466 if (tty_port_suspended(port)) {
2467 const struct uart_ops *ops = uport->ops;
2470 uart_change_pm(state, UART_PM_STATE_ON);
2471 spin_lock_irq(&uport->lock);
2472 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2473 ops->set_mctrl(uport, 0);
2474 spin_unlock_irq(&uport->lock);
2475 if (console_suspend_enabled || !uart_console(uport)) {
2476 /* Protected by port mutex for now */
2477 struct tty_struct *tty = port->tty;
2479 ret = ops->startup(uport);
2482 uart_change_line_settings(tty, state, NULL);
2483 spin_lock_irq(&uport->lock);
2484 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2485 ops->set_mctrl(uport, uport->mctrl);
2487 uart_rs485_config(uport);
2488 ops->start_tx(uport);
2489 spin_unlock_irq(&uport->lock);
2490 tty_port_set_initialized(port, true);
2493 * Failed to resume - maybe hardware went away?
2494 * Clear the "initialized" flag so we won't try
2495 * to call the low level drivers shutdown method.
2497 uart_shutdown(tty, state);
2501 tty_port_set_suspended(port, false);
2504 mutex_unlock(&port->mutex);
2508 EXPORT_SYMBOL(uart_resume_port);
2511 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2515 switch (port->iotype) {
2517 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2520 snprintf(address, sizeof(address),
2521 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2529 snprintf(address, sizeof(address),
2530 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2533 strscpy(address, "*unknown*", sizeof(address));
2537 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2538 port->dev ? dev_name(port->dev) : "",
2539 port->dev ? ": " : "",
2541 address, port->irq, port->uartclk / 16, uart_type(port));
2543 /* The magic multiplier feature is a bit obscure, so report it too. */
2544 if (port->flags & UPF_MAGIC_MULTIPLIER)
2545 pr_info("%s%s%s extra baud rates supported: %d, %d",
2546 port->dev ? dev_name(port->dev) : "",
2547 port->dev ? ": " : "",
2549 port->uartclk / 8, port->uartclk / 4);
2553 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2554 struct uart_port *port)
2559 * If there isn't a port here, don't do anything further.
2561 if (!port->iobase && !port->mapbase && !port->membase)
2565 * Now do the auto configuration stuff. Note that config_port
2566 * is expected to claim the resources and map the port for us.
2569 if (port->flags & UPF_AUTO_IRQ)
2570 flags |= UART_CONFIG_IRQ;
2571 if (port->flags & UPF_BOOT_AUTOCONF) {
2572 if (!(port->flags & UPF_FIXED_TYPE)) {
2573 port->type = PORT_UNKNOWN;
2574 flags |= UART_CONFIG_TYPE;
2576 port->ops->config_port(port, flags);
2579 if (port->type != PORT_UNKNOWN) {
2580 unsigned long flags;
2582 uart_report_port(drv, port);
2584 /* Power up port for set_mctrl() */
2585 uart_change_pm(state, UART_PM_STATE_ON);
2588 * Ensure that the modem control lines are de-activated.
2589 * keep the DTR setting that is set in uart_set_options()
2590 * We probably don't need a spinlock around this, but
2592 spin_lock_irqsave(&port->lock, flags);
2593 port->mctrl &= TIOCM_DTR;
2594 if (!(port->rs485.flags & SER_RS485_ENABLED))
2595 port->ops->set_mctrl(port, port->mctrl);
2597 uart_rs485_config(port);
2598 spin_unlock_irqrestore(&port->lock, flags);
2601 * If this driver supports console, and it hasn't been
2602 * successfully registered yet, try to re-register it.
2603 * It may be that the port was not available.
2605 if (port->cons && !console_is_registered(port->cons))
2606 register_console(port->cons);
2609 * Power down all ports by default, except the
2610 * console if we have one.
2612 if (!uart_console(port))
2613 uart_change_pm(state, UART_PM_STATE_OFF);
2617 #ifdef CONFIG_CONSOLE_POLL
2619 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2621 struct uart_driver *drv = driver->driver_state;
2622 struct uart_state *state = drv->state + line;
2623 enum uart_pm_state pm_state;
2624 struct tty_port *tport;
2625 struct uart_port *port;
2632 tport = &state->port;
2633 mutex_lock(&tport->mutex);
2635 port = uart_port_check(state);
2636 if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2641 pm_state = state->pm_state;
2642 uart_change_pm(state, UART_PM_STATE_ON);
2644 if (port->ops->poll_init) {
2646 * We don't set initialized as we only initialized the hw,
2647 * e.g. state->xmit is still uninitialized.
2649 if (!tty_port_initialized(tport))
2650 ret = port->ops->poll_init(port);
2653 if (!ret && options) {
2654 uart_parse_options(options, &baud, &parity, &bits, &flow);
2655 console_list_lock();
2656 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2657 console_list_unlock();
2661 uart_change_pm(state, pm_state);
2662 mutex_unlock(&tport->mutex);
2666 static int uart_poll_get_char(struct tty_driver *driver, int line)
2668 struct uart_driver *drv = driver->driver_state;
2669 struct uart_state *state = drv->state + line;
2670 struct uart_port *port;
2673 port = uart_port_ref(state);
2675 ret = port->ops->poll_get_char(port);
2676 uart_port_deref(port);
2682 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2684 struct uart_driver *drv = driver->driver_state;
2685 struct uart_state *state = drv->state + line;
2686 struct uart_port *port;
2688 port = uart_port_ref(state);
2693 port->ops->poll_put_char(port, '\r');
2694 port->ops->poll_put_char(port, ch);
2695 uart_port_deref(port);
2699 static const struct tty_operations uart_ops = {
2700 .install = uart_install,
2702 .close = uart_close,
2703 .write = uart_write,
2704 .put_char = uart_put_char,
2705 .flush_chars = uart_flush_chars,
2706 .write_room = uart_write_room,
2707 .chars_in_buffer= uart_chars_in_buffer,
2708 .flush_buffer = uart_flush_buffer,
2709 .ioctl = uart_ioctl,
2710 .throttle = uart_throttle,
2711 .unthrottle = uart_unthrottle,
2712 .send_xchar = uart_send_xchar,
2713 .set_termios = uart_set_termios,
2714 .set_ldisc = uart_set_ldisc,
2716 .start = uart_start,
2717 .hangup = uart_hangup,
2718 .break_ctl = uart_break_ctl,
2719 .wait_until_sent= uart_wait_until_sent,
2720 #ifdef CONFIG_PROC_FS
2721 .proc_show = uart_proc_show,
2723 .tiocmget = uart_tiocmget,
2724 .tiocmset = uart_tiocmset,
2725 .set_serial = uart_set_info_user,
2726 .get_serial = uart_get_info_user,
2727 .get_icount = uart_get_icount,
2728 #ifdef CONFIG_CONSOLE_POLL
2729 .poll_init = uart_poll_init,
2730 .poll_get_char = uart_poll_get_char,
2731 .poll_put_char = uart_poll_put_char,
2735 static const struct tty_port_operations uart_port_ops = {
2736 .carrier_raised = uart_carrier_raised,
2737 .dtr_rts = uart_dtr_rts,
2738 .activate = uart_port_activate,
2739 .shutdown = uart_tty_port_shutdown,
2743 * uart_register_driver - register a driver with the uart core layer
2744 * @drv: low level driver structure
2746 * Register a uart driver with the core driver. We in turn register with the
2747 * tty layer, and initialise the core driver per-port state.
2749 * We have a proc file in /proc/tty/driver which is named after the normal
2752 * @drv->port should be %NULL, and the per-port structures should be registered
2753 * using uart_add_one_port() after this call has succeeded.
2755 * Locking: none, Interrupts: enabled
2757 int uart_register_driver(struct uart_driver *drv)
2759 struct tty_driver *normal;
2760 int i, retval = -ENOMEM;
2765 * Maybe we should be using a slab cache for this, especially if
2766 * we have a large number of ports to handle.
2768 drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2772 normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
2773 TTY_DRIVER_DYNAMIC_DEV);
2774 if (IS_ERR(normal)) {
2775 retval = PTR_ERR(normal);
2779 drv->tty_driver = normal;
2781 normal->driver_name = drv->driver_name;
2782 normal->name = drv->dev_name;
2783 normal->major = drv->major;
2784 normal->minor_start = drv->minor;
2785 normal->type = TTY_DRIVER_TYPE_SERIAL;
2786 normal->subtype = SERIAL_TYPE_NORMAL;
2787 normal->init_termios = tty_std_termios;
2788 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2789 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2790 normal->driver_state = drv;
2791 tty_set_operations(normal, &uart_ops);
2794 * Initialise the UART state(s).
2796 for (i = 0; i < drv->nr; i++) {
2797 struct uart_state *state = drv->state + i;
2798 struct tty_port *port = &state->port;
2800 tty_port_init(port);
2801 port->ops = &uart_port_ops;
2804 retval = tty_register_driver(normal);
2808 for (i = 0; i < drv->nr; i++)
2809 tty_port_destroy(&drv->state[i].port);
2810 tty_driver_kref_put(normal);
2816 EXPORT_SYMBOL(uart_register_driver);
2819 * uart_unregister_driver - remove a driver from the uart core layer
2820 * @drv: low level driver structure
2822 * Remove all references to a driver from the core driver. The low level
2823 * driver must have removed all its ports via the uart_remove_one_port() if it
2824 * registered them with uart_add_one_port(). (I.e. @drv->port is %NULL.)
2826 * Locking: none, Interrupts: enabled
2828 void uart_unregister_driver(struct uart_driver *drv)
2830 struct tty_driver *p = drv->tty_driver;
2833 tty_unregister_driver(p);
2834 tty_driver_kref_put(p);
2835 for (i = 0; i < drv->nr; i++)
2836 tty_port_destroy(&drv->state[i].port);
2839 drv->tty_driver = NULL;
2841 EXPORT_SYMBOL(uart_unregister_driver);
2843 struct tty_driver *uart_console_device(struct console *co, int *index)
2845 struct uart_driver *p = co->data;
2847 return p->tty_driver;
2849 EXPORT_SYMBOL_GPL(uart_console_device);
2851 static ssize_t uartclk_show(struct device *dev,
2852 struct device_attribute *attr, char *buf)
2854 struct serial_struct tmp;
2855 struct tty_port *port = dev_get_drvdata(dev);
2857 uart_get_info(port, &tmp);
2858 return sprintf(buf, "%d\n", tmp.baud_base * 16);
2861 static ssize_t type_show(struct device *dev,
2862 struct device_attribute *attr, char *buf)
2864 struct serial_struct tmp;
2865 struct tty_port *port = dev_get_drvdata(dev);
2867 uart_get_info(port, &tmp);
2868 return sprintf(buf, "%d\n", tmp.type);
2871 static ssize_t line_show(struct device *dev,
2872 struct device_attribute *attr, char *buf)
2874 struct serial_struct tmp;
2875 struct tty_port *port = dev_get_drvdata(dev);
2877 uart_get_info(port, &tmp);
2878 return sprintf(buf, "%d\n", tmp.line);
2881 static ssize_t port_show(struct device *dev,
2882 struct device_attribute *attr, char *buf)
2884 struct serial_struct tmp;
2885 struct tty_port *port = dev_get_drvdata(dev);
2886 unsigned long ioaddr;
2888 uart_get_info(port, &tmp);
2890 if (HIGH_BITS_OFFSET)
2891 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2892 return sprintf(buf, "0x%lX\n", ioaddr);
2895 static ssize_t irq_show(struct device *dev,
2896 struct device_attribute *attr, char *buf)
2898 struct serial_struct tmp;
2899 struct tty_port *port = dev_get_drvdata(dev);
2901 uart_get_info(port, &tmp);
2902 return sprintf(buf, "%d\n", tmp.irq);
2905 static ssize_t flags_show(struct device *dev,
2906 struct device_attribute *attr, char *buf)
2908 struct serial_struct tmp;
2909 struct tty_port *port = dev_get_drvdata(dev);
2911 uart_get_info(port, &tmp);
2912 return sprintf(buf, "0x%X\n", tmp.flags);
2915 static ssize_t xmit_fifo_size_show(struct device *dev,
2916 struct device_attribute *attr, char *buf)
2918 struct serial_struct tmp;
2919 struct tty_port *port = dev_get_drvdata(dev);
2921 uart_get_info(port, &tmp);
2922 return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2925 static ssize_t close_delay_show(struct device *dev,
2926 struct device_attribute *attr, char *buf)
2928 struct serial_struct tmp;
2929 struct tty_port *port = dev_get_drvdata(dev);
2931 uart_get_info(port, &tmp);
2932 return sprintf(buf, "%d\n", tmp.close_delay);
2935 static ssize_t closing_wait_show(struct device *dev,
2936 struct device_attribute *attr, char *buf)
2938 struct serial_struct tmp;
2939 struct tty_port *port = dev_get_drvdata(dev);
2941 uart_get_info(port, &tmp);
2942 return sprintf(buf, "%d\n", tmp.closing_wait);
2945 static ssize_t custom_divisor_show(struct device *dev,
2946 struct device_attribute *attr, char *buf)
2948 struct serial_struct tmp;
2949 struct tty_port *port = dev_get_drvdata(dev);
2951 uart_get_info(port, &tmp);
2952 return sprintf(buf, "%d\n", tmp.custom_divisor);
2955 static ssize_t io_type_show(struct device *dev,
2956 struct device_attribute *attr, char *buf)
2958 struct serial_struct tmp;
2959 struct tty_port *port = dev_get_drvdata(dev);
2961 uart_get_info(port, &tmp);
2962 return sprintf(buf, "%d\n", tmp.io_type);
2965 static ssize_t iomem_base_show(struct device *dev,
2966 struct device_attribute *attr, char *buf)
2968 struct serial_struct tmp;
2969 struct tty_port *port = dev_get_drvdata(dev);
2971 uart_get_info(port, &tmp);
2972 return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
2975 static ssize_t iomem_reg_shift_show(struct device *dev,
2976 struct device_attribute *attr, char *buf)
2978 struct serial_struct tmp;
2979 struct tty_port *port = dev_get_drvdata(dev);
2981 uart_get_info(port, &tmp);
2982 return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
2985 static ssize_t console_show(struct device *dev,
2986 struct device_attribute *attr, char *buf)
2988 struct tty_port *port = dev_get_drvdata(dev);
2989 struct uart_state *state = container_of(port, struct uart_state, port);
2990 struct uart_port *uport;
2991 bool console = false;
2993 mutex_lock(&port->mutex);
2994 uport = uart_port_check(state);
2996 console = uart_console_registered(uport);
2997 mutex_unlock(&port->mutex);
2999 return sprintf(buf, "%c\n", console ? 'Y' : 'N');
3002 static ssize_t console_store(struct device *dev,
3003 struct device_attribute *attr, const char *buf, size_t count)
3005 struct tty_port *port = dev_get_drvdata(dev);
3006 struct uart_state *state = container_of(port, struct uart_state, port);
3007 struct uart_port *uport;
3008 bool oldconsole, newconsole;
3011 ret = kstrtobool(buf, &newconsole);
3015 mutex_lock(&port->mutex);
3016 uport = uart_port_check(state);
3018 oldconsole = uart_console_registered(uport);
3019 if (oldconsole && !newconsole) {
3020 ret = unregister_console(uport->cons);
3021 } else if (!oldconsole && newconsole) {
3022 if (uart_console(uport)) {
3023 uport->console_reinit = 1;
3024 register_console(uport->cons);
3032 mutex_unlock(&port->mutex);
3034 return ret < 0 ? ret : count;
3037 static DEVICE_ATTR_RO(uartclk);
3038 static DEVICE_ATTR_RO(type);
3039 static DEVICE_ATTR_RO(line);
3040 static DEVICE_ATTR_RO(port);
3041 static DEVICE_ATTR_RO(irq);
3042 static DEVICE_ATTR_RO(flags);
3043 static DEVICE_ATTR_RO(xmit_fifo_size);
3044 static DEVICE_ATTR_RO(close_delay);
3045 static DEVICE_ATTR_RO(closing_wait);
3046 static DEVICE_ATTR_RO(custom_divisor);
3047 static DEVICE_ATTR_RO(io_type);
3048 static DEVICE_ATTR_RO(iomem_base);
3049 static DEVICE_ATTR_RO(iomem_reg_shift);
3050 static DEVICE_ATTR_RW(console);
3052 static struct attribute *tty_dev_attrs[] = {
3053 &dev_attr_uartclk.attr,
3054 &dev_attr_type.attr,
3055 &dev_attr_line.attr,
3056 &dev_attr_port.attr,
3058 &dev_attr_flags.attr,
3059 &dev_attr_xmit_fifo_size.attr,
3060 &dev_attr_close_delay.attr,
3061 &dev_attr_closing_wait.attr,
3062 &dev_attr_custom_divisor.attr,
3063 &dev_attr_io_type.attr,
3064 &dev_attr_iomem_base.attr,
3065 &dev_attr_iomem_reg_shift.attr,
3066 &dev_attr_console.attr,
3070 static const struct attribute_group tty_dev_attr_group = {
3071 .attrs = tty_dev_attrs,
3075 * serial_core_add_one_port - attach a driver-defined port structure
3076 * @drv: pointer to the uart low level driver structure for this port
3077 * @uport: uart port structure to use for this port.
3079 * Context: task context, might sleep
3081 * This allows the driver @drv to register its own uart_port structure with the
3082 * core driver. The main purpose is to allow the low level uart drivers to
3083 * expand uart_port, rather than having yet more levels of structures.
3084 * Caller must hold port_mutex.
3086 static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *uport)
3088 struct uart_state *state;
3089 struct tty_port *port;
3091 struct device *tty_dev;
3094 if (uport->line >= drv->nr)
3097 state = drv->state + uport->line;
3098 port = &state->port;
3100 mutex_lock(&port->mutex);
3101 if (state->uart_port) {
3106 /* Link the port to the driver state table and vice versa */
3107 atomic_set(&state->refcount, 1);
3108 init_waitqueue_head(&state->remove_wait);
3109 state->uart_port = uport;
3110 uport->state = state;
3112 state->pm_state = UART_PM_STATE_UNDEFINED;
3113 uport->cons = drv->cons;
3114 uport->minor = drv->tty_driver->minor_start + uport->line;
3115 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
3116 drv->tty_driver->name_base + uport->line);
3123 * If this port is in use as a console then the spinlock is already
3126 if (!uart_console_registered(uport))
3127 uart_port_spin_lock_init(uport);
3129 if (uport->cons && uport->dev)
3130 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
3132 tty_port_link_device(port, drv->tty_driver, uport->line);
3133 uart_configure_port(drv, state, uport);
3135 port->console = uart_console(uport);
3138 if (uport->attr_group)
3141 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
3143 if (!uport->tty_groups) {
3147 uport->tty_groups[0] = &tty_dev_attr_group;
3148 if (uport->attr_group)
3149 uport->tty_groups[1] = uport->attr_group;
3152 * Register the port whether it's detected or not. This allows
3153 * setserial to be used to alter this port's parameters.
3155 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
3156 uport->line, uport->dev, port, uport->tty_groups);
3157 if (!IS_ERR(tty_dev)) {
3158 device_set_wakeup_capable(tty_dev, 1);
3160 dev_err(uport->dev, "Cannot register tty device on line %d\n",
3165 mutex_unlock(&port->mutex);
3171 * serial_core_remove_one_port - detach a driver defined port structure
3172 * @drv: pointer to the uart low level driver structure for this port
3173 * @uport: uart port structure for this port
3175 * Context: task context, might sleep
3177 * This unhooks (and hangs up) the specified port structure from the core
3178 * driver. No further calls will be made to the low-level code for this port.
3179 * Caller must hold port_mutex.
3181 static void serial_core_remove_one_port(struct uart_driver *drv,
3182 struct uart_port *uport)
3184 struct uart_state *state = drv->state + uport->line;
3185 struct tty_port *port = &state->port;
3186 struct uart_port *uart_port;
3187 struct tty_struct *tty;
3189 mutex_lock(&port->mutex);
3190 uart_port = uart_port_check(state);
3191 if (uart_port != uport)
3192 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
3196 mutex_unlock(&port->mutex);
3199 mutex_unlock(&port->mutex);
3202 * Remove the devices from the tty layer
3204 tty_port_unregister_device(port, drv->tty_driver, uport->line);
3206 tty = tty_port_tty_get(port);
3208 tty_vhangup(port->tty);
3213 * If the port is used as a console, unregister it
3215 if (uart_console(uport))
3216 unregister_console(uport->cons);
3219 * Free the port IO and memory resources, if any.
3221 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3222 uport->ops->release_port(uport);
3223 kfree(uport->tty_groups);
3227 * Indicate that there isn't a port here anymore.
3229 uport->type = PORT_UNKNOWN;
3230 uport->port_dev = NULL;
3232 mutex_lock(&port->mutex);
3233 WARN_ON(atomic_dec_return(&state->refcount) < 0);
3234 wait_event(state->remove_wait, !atomic_read(&state->refcount));
3235 state->uart_port = NULL;
3236 mutex_unlock(&port->mutex);
3240 * uart_match_port - are the two ports equivalent?
3241 * @port1: first port
3242 * @port2: second port
3244 * This utility function can be used to determine whether two uart_port
3245 * structures describe the same port.
3247 bool uart_match_port(const struct uart_port *port1,
3248 const struct uart_port *port2)
3250 if (port1->iotype != port2->iotype)
3253 switch (port1->iotype) {
3255 return port1->iobase == port2->iobase;
3257 return port1->iobase == port2->iobase &&
3258 port1->hub6 == port2->hub6;
3265 return port1->mapbase == port2->mapbase;
3270 EXPORT_SYMBOL(uart_match_port);
3272 static struct serial_ctrl_device *
3273 serial_core_get_ctrl_dev(struct serial_port_device *port_dev)
3275 struct device *dev = &port_dev->dev;
3277 return to_serial_base_ctrl_device(dev->parent);
3281 * Find a registered serial core controller device if one exists. Returns
3282 * the first device matching the ctrl_id. Caller must hold port_mutex.
3284 static struct serial_ctrl_device *serial_core_ctrl_find(struct uart_driver *drv,
3285 struct device *phys_dev,
3288 struct uart_state *state;
3291 lockdep_assert_held(&port_mutex);
3293 for (i = 0; i < drv->nr; i++) {
3294 state = drv->state + i;
3295 if (!state->uart_port || !state->uart_port->port_dev)
3298 if (state->uart_port->dev == phys_dev &&
3299 state->uart_port->ctrl_id == ctrl_id)
3300 return serial_core_get_ctrl_dev(state->uart_port->port_dev);
3306 static struct serial_ctrl_device *serial_core_ctrl_device_add(struct uart_port *port)
3308 return serial_base_ctrl_add(port, port->dev);
3311 static int serial_core_port_device_add(struct serial_ctrl_device *ctrl_dev,
3312 struct uart_port *port)
3314 struct serial_port_device *port_dev;
3316 port_dev = serial_base_port_add(port, ctrl_dev);
3317 if (IS_ERR(port_dev))
3318 return PTR_ERR(port_dev);
3320 port->port_dev = port_dev;
3326 * Initialize a serial core port device, and a controller device if needed.
3328 int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
3330 struct serial_ctrl_device *ctrl_dev, *new_ctrl_dev = NULL;
3333 mutex_lock(&port_mutex);
3336 * Prevent serial_port_runtime_resume() from trying to use the port
3337 * until serial_core_add_one_port() has completed
3339 port->flags |= UPF_DEAD;
3341 /* Inititalize a serial core controller device if needed */
3342 ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
3344 new_ctrl_dev = serial_core_ctrl_device_add(port);
3345 if (IS_ERR(new_ctrl_dev)) {
3346 ret = PTR_ERR(new_ctrl_dev);
3349 ctrl_dev = new_ctrl_dev;
3353 * Initialize a serial core port device. Tag the port dead to prevent
3354 * serial_port_runtime_resume() trying to do anything until port has
3355 * been registered. It gets cleared by serial_core_add_one_port().
3357 ret = serial_core_port_device_add(ctrl_dev, port);
3359 goto err_unregister_ctrl_dev;
3361 ret = serial_core_add_one_port(drv, port);
3363 goto err_unregister_port_dev;
3365 port->flags &= ~UPF_DEAD;
3367 mutex_unlock(&port_mutex);
3371 err_unregister_port_dev:
3372 serial_base_port_device_remove(port->port_dev);
3374 err_unregister_ctrl_dev:
3375 serial_base_ctrl_device_remove(new_ctrl_dev);
3378 mutex_unlock(&port_mutex);
3384 * Removes a serial core port device, and the related serial core controller
3385 * device if the last instance.
3387 void serial_core_unregister_port(struct uart_driver *drv, struct uart_port *port)
3389 struct device *phys_dev = port->dev;
3390 struct serial_port_device *port_dev = port->port_dev;
3391 struct serial_ctrl_device *ctrl_dev = serial_core_get_ctrl_dev(port_dev);
3392 int ctrl_id = port->ctrl_id;
3394 mutex_lock(&port_mutex);
3396 port->flags |= UPF_DEAD;
3398 serial_core_remove_one_port(drv, port);
3400 /* Note that struct uart_port *port is no longer valid at this point */
3401 serial_base_port_device_remove(port_dev);
3403 /* Drop the serial core controller device if no ports are using it */
3404 if (!serial_core_ctrl_find(drv, phys_dev, ctrl_id))
3405 serial_base_ctrl_device_remove(ctrl_dev);
3407 mutex_unlock(&port_mutex);
3411 * uart_handle_dcd_change - handle a change of carrier detect state
3412 * @uport: uart_port structure for the open port
3413 * @active: new carrier detect status
3415 * Caller must hold uport->lock.
3417 void uart_handle_dcd_change(struct uart_port *uport, bool active)
3419 struct tty_port *port = &uport->state->port;
3420 struct tty_struct *tty = port->tty;
3421 struct tty_ldisc *ld;
3423 lockdep_assert_held_once(&uport->lock);
3426 ld = tty_ldisc_ref(tty);
3428 if (ld->ops->dcd_change)
3429 ld->ops->dcd_change(tty, active);
3430 tty_ldisc_deref(ld);
3434 uport->icount.dcd++;
3436 if (uart_dcd_enabled(uport)) {
3438 wake_up_interruptible(&port->open_wait);
3443 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3446 * uart_handle_cts_change - handle a change of clear-to-send state
3447 * @uport: uart_port structure for the open port
3448 * @active: new clear-to-send status
3450 * Caller must hold uport->lock.
3452 void uart_handle_cts_change(struct uart_port *uport, bool active)
3454 lockdep_assert_held_once(&uport->lock);
3456 uport->icount.cts++;
3458 if (uart_softcts_mode(uport)) {
3459 if (uport->hw_stopped) {
3461 uport->hw_stopped = false;
3462 uport->ops->start_tx(uport);
3463 uart_write_wakeup(uport);
3467 uport->hw_stopped = true;
3468 uport->ops->stop_tx(uport);
3474 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3477 * uart_insert_char - push a char to the uart layer
3479 * User is responsible to call tty_flip_buffer_push when they are done with
3482 * @port: corresponding port
3483 * @status: state of the serial port RX buffer (LSR for 8250)
3484 * @overrun: mask of overrun bits in @status
3485 * @ch: character to push
3486 * @flag: flag for the character (see TTY_NORMAL and friends)
3488 void uart_insert_char(struct uart_port *port, unsigned int status,
3489 unsigned int overrun, unsigned int ch, unsigned int flag)
3491 struct tty_port *tport = &port->state->port;
3493 if ((status & port->ignore_status_mask & ~overrun) == 0)
3494 if (tty_insert_flip_char(tport, ch, flag) == 0)
3495 ++port->icount.buf_overrun;
3498 * Overrun is special. Since it's reported immediately,
3499 * it doesn't affect the current character.
3501 if (status & ~port->ignore_status_mask & overrun)
3502 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3503 ++port->icount.buf_overrun;
3505 EXPORT_SYMBOL_GPL(uart_insert_char);
3507 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3508 static const char sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3510 static void uart_sysrq_on(struct work_struct *w)
3512 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3514 sysrq_toggle_support(1);
3515 pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3516 sysrq_toggle_seq_len, sysrq_toggle_seq);
3518 static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3521 * uart_try_toggle_sysrq - Enables SysRq from serial line
3522 * @port: uart_port structure where char(s) after BREAK met
3523 * @ch: new character in the sequence after received BREAK
3525 * Enables magic SysRq when the required sequence is met on port
3526 * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3528 * Returns: %false if @ch is out of enabling sequence and should be
3529 * handled some other way, %true if @ch was consumed.
3531 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
3533 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3535 if (!sysrq_toggle_seq_len)
3538 BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3539 if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3540 port->sysrq_seq = 0;
3544 if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3545 port->sysrq = jiffies + SYSRQ_TIMEOUT;
3549 schedule_work(&sysrq_enable_work);
3554 EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3558 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3559 * @port: uart device's target port
3561 * This function implements the device tree binding described in
3562 * Documentation/devicetree/bindings/serial/rs485.txt.
3564 int uart_get_rs485_mode(struct uart_port *port)
3566 struct serial_rs485 *rs485conf = &port->rs485;
3567 struct device *dev = port->dev;
3570 int rx_during_tx_gpio_flag;
3572 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3575 rs485conf->delay_rts_before_send = rs485_delay[0];
3576 rs485conf->delay_rts_after_send = rs485_delay[1];
3578 rs485conf->delay_rts_before_send = 0;
3579 rs485conf->delay_rts_after_send = 0;
3582 uart_sanitize_serial_rs485_delays(port, rs485conf);
3585 * Clear full-duplex and enabled flags, set RTS polarity to active high
3586 * to get to a defined state with the following properties:
3588 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3589 SER_RS485_TERMINATE_BUS |
3590 SER_RS485_RTS_AFTER_SEND);
3591 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3593 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3594 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3596 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3597 rs485conf->flags |= SER_RS485_ENABLED;
3599 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3600 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3601 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3605 * Disabling termination by default is the safe choice: Else if many
3606 * bus participants enable it, no communication is possible at all.
3607 * Works fine for short cables and users may enable for longer cables.
3609 port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
3611 if (IS_ERR(port->rs485_term_gpio)) {
3612 ret = PTR_ERR(port->rs485_term_gpio);
3613 port->rs485_term_gpio = NULL;
3614 return dev_err_probe(dev, ret, "Cannot get rs485-term-gpios\n");
3616 if (port->rs485_term_gpio)
3617 port->rs485_supported.flags |= SER_RS485_TERMINATE_BUS;
3619 rx_during_tx_gpio_flag = (rs485conf->flags & SER_RS485_RX_DURING_TX) ?
3620 GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
3621 port->rs485_rx_during_tx_gpio = devm_gpiod_get_optional(dev,
3622 "rs485-rx-during-tx",
3623 rx_during_tx_gpio_flag);
3624 if (IS_ERR(port->rs485_rx_during_tx_gpio)) {
3625 ret = PTR_ERR(port->rs485_rx_during_tx_gpio);
3626 port->rs485_rx_during_tx_gpio = NULL;
3627 return dev_err_probe(dev, ret, "Cannot get rs485-rx-during-tx-gpios\n");
3632 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3634 /* Compile-time assertions for serial_rs485 layout */
3635 static_assert(offsetof(struct serial_rs485, padding) ==
3636 (offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));
3637 static_assert(offsetof(struct serial_rs485, padding1) ==
3638 offsetof(struct serial_rs485, padding[1]));
3639 static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) ==
3640 sizeof(struct serial_rs485));
3642 MODULE_DESCRIPTION("Serial driver core");
3643 MODULE_LICENSE("GPL");