1 // SPDX-License-Identifier: GPL-2.0+
3 * Driver core for serial ports
5 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
7 * Copyright 1999 ARM Limited
8 * Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
10 #include <linux/module.h>
11 #include <linux/tty.h>
12 #include <linux/tty_flip.h>
13 #include <linux/slab.h>
14 #include <linux/sched/signal.h>
15 #include <linux/init.h>
16 #include <linux/console.h>
18 #include <linux/proc_fs.h>
19 #include <linux/seq_file.h>
20 #include <linux/device.h>
21 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
22 #include <linux/serial_core.h>
23 #include <linux/delay.h>
24 #include <linux/mutex.h>
26 #include <linux/irq.h>
27 #include <linux/uaccess.h>
30 * This is used to lock changes in serial line configuration.
32 static DEFINE_MUTEX(port_mutex);
35 * lockdep: port->lock is initialized in two places, but we
36 * want only one lock-class:
38 static struct lock_class_key port_lock_key;
40 #define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
42 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
43 struct ktermios *old_termios);
44 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
45 static void uart_change_pm(struct uart_state *state,
46 enum uart_pm_state pm_state);
48 static void uart_port_shutdown(struct tty_port *port);
50 static int uart_dcd_enabled(struct uart_port *uport)
52 return !!(uport->status & UPSTAT_DCD_ENABLE);
55 static inline struct uart_port *uart_port_ref(struct uart_state *state)
57 if (atomic_add_unless(&state->refcount, 1, 0))
58 return state->uart_port;
62 static inline void uart_port_deref(struct uart_port *uport)
64 if (atomic_dec_and_test(&uport->state->refcount))
65 wake_up(&uport->state->remove_wait);
68 #define uart_port_lock(state, flags) \
70 struct uart_port *__uport = uart_port_ref(state); \
72 spin_lock_irqsave(&__uport->lock, flags); \
76 #define uart_port_unlock(uport, flags) \
78 struct uart_port *__uport = uport; \
80 spin_unlock_irqrestore(&__uport->lock, flags); \
81 uart_port_deref(__uport); \
85 static inline struct uart_port *uart_port_check(struct uart_state *state)
87 lockdep_assert_held(&state->port.mutex);
88 return state->uart_port;
92 * This routine is used by the interrupt handler to schedule processing in
93 * the software interrupt portion of the driver.
95 void uart_write_wakeup(struct uart_port *port)
97 struct uart_state *state = port->state;
99 * This means you called this function _after_ the port was
100 * closed. No cookie for you.
103 tty_port_tty_wakeup(&state->port);
106 static void uart_stop(struct tty_struct *tty)
108 struct uart_state *state = tty->driver_data;
109 struct uart_port *port;
112 port = uart_port_lock(state, flags);
114 port->ops->stop_tx(port);
115 uart_port_unlock(port, flags);
118 static void __uart_start(struct tty_struct *tty)
120 struct uart_state *state = tty->driver_data;
121 struct uart_port *port = state->uart_port;
123 if (port && !uart_tx_stopped(port))
124 port->ops->start_tx(port);
127 static void uart_start(struct tty_struct *tty)
129 struct uart_state *state = tty->driver_data;
130 struct uart_port *port;
133 port = uart_port_lock(state, flags);
135 uart_port_unlock(port, flags);
139 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
144 spin_lock_irqsave(&port->lock, flags);
146 port->mctrl = (old & ~clear) | set;
147 if (old != port->mctrl)
148 port->ops->set_mctrl(port, port->mctrl);
149 spin_unlock_irqrestore(&port->lock, flags);
152 #define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
153 #define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
155 static void uart_port_dtr_rts(struct uart_port *uport, int raise)
157 int rs485_on = uport->rs485_config &&
158 (uport->rs485.flags & SER_RS485_ENABLED);
159 int RTS_after_send = !!(uport->rs485.flags & SER_RS485_RTS_AFTER_SEND);
162 if (rs485_on && !RTS_after_send) {
163 uart_set_mctrl(uport, TIOCM_DTR);
164 uart_clear_mctrl(uport, TIOCM_RTS);
166 uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
169 unsigned int clear = TIOCM_DTR;
171 clear |= (!rs485_on || !RTS_after_send) ? TIOCM_RTS : 0;
172 uart_clear_mctrl(uport, clear);
177 * Startup the port. This will be called once per open. All calls
178 * will be serialised by the per-port mutex.
180 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
183 struct uart_port *uport = uart_port_check(state);
185 unsigned long flags = 0;
188 if (uport->type == PORT_UNKNOWN)
192 * Make sure the device is in D0 state.
194 uart_change_pm(state, UART_PM_STATE_ON);
197 * Initialise and allocate the transmit and temporary
200 page = get_zeroed_page(GFP_KERNEL);
204 uart_port_lock(state, flags);
205 if (!state->xmit.buf) {
206 state->xmit.buf = (unsigned char *) page;
207 uart_circ_clear(&state->xmit);
208 uart_port_unlock(uport, flags);
210 uart_port_unlock(uport, flags);
212 * Do not free() the page under the port lock, see
218 retval = uport->ops->startup(uport);
220 if (uart_console(uport) && uport->cons->cflag) {
221 tty->termios.c_cflag = uport->cons->cflag;
222 uport->cons->cflag = 0;
225 * Initialise the hardware port settings.
227 uart_change_speed(tty, state, NULL);
230 * Setup the RTS and DTR signals once the
231 * port is open and ready to respond.
233 if (init_hw && C_BAUD(tty))
234 uart_port_dtr_rts(uport, 1);
238 * This is to allow setserial on this port. People may want to set
239 * port/irq/type and then reconfigure the port properly if it failed
242 if (retval && capable(CAP_SYS_ADMIN))
248 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
251 struct tty_port *port = &state->port;
254 if (tty_port_initialized(port))
257 retval = uart_port_startup(tty, state, init_hw);
259 set_bit(TTY_IO_ERROR, &tty->flags);
265 * This routine will shutdown a serial port; interrupts are disabled, and
266 * DTR is dropped if the hangup on close termio flag is on. Calls to
267 * uart_shutdown are serialised by the per-port semaphore.
269 * uport == NULL if uart_port has already been removed
271 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
273 struct uart_port *uport = uart_port_check(state);
274 struct tty_port *port = &state->port;
275 unsigned long flags = 0;
276 char *xmit_buf = NULL;
279 * Set the TTY IO error marker
282 set_bit(TTY_IO_ERROR, &tty->flags);
284 if (tty_port_initialized(port)) {
285 tty_port_set_initialized(port, 0);
288 * Turn off DTR and RTS early.
290 if (uport && uart_console(uport) && tty)
291 uport->cons->cflag = tty->termios.c_cflag;
293 if (!tty || C_HUPCL(tty))
294 uart_port_dtr_rts(uport, 0);
296 uart_port_shutdown(port);
300 * It's possible for shutdown to be called after suspend if we get
301 * a DCD drop (hangup) at just the right time. Clear suspended bit so
302 * we don't try to resume a port that has been shutdown.
304 tty_port_set_suspended(port, 0);
307 * Do not free() the transmit buffer page under the port lock since
308 * this can create various circular locking scenarios. For instance,
309 * console driver may need to allocate/free a debug object, which
310 * can endup in printk() recursion.
312 uart_port_lock(state, flags);
313 xmit_buf = state->xmit.buf;
314 state->xmit.buf = NULL;
315 uart_port_unlock(uport, flags);
318 free_page((unsigned long)xmit_buf);
322 * uart_update_timeout - update per-port FIFO timeout.
323 * @port: uart_port structure describing the port
324 * @cflag: termios cflag value
325 * @baud: speed of the port
327 * Set the port FIFO timeout value. The @cflag value should
328 * reflect the actual hardware settings.
331 uart_update_timeout(struct uart_port *port, unsigned int cflag,
336 /* byte size and parity */
337 switch (cflag & CSIZE) {
358 * The total number of bits to be transmitted in the fifo.
360 bits = bits * port->fifosize;
363 * Figure the timeout to send the above number of bits.
364 * Add .02 seconds of slop
366 port->timeout = (HZ * bits) / baud + HZ/50;
369 EXPORT_SYMBOL(uart_update_timeout);
372 * uart_get_baud_rate - return baud rate for a particular port
373 * @port: uart_port structure describing the port in question.
374 * @termios: desired termios settings.
375 * @old: old termios (or NULL)
376 * @min: minimum acceptable baud rate
377 * @max: maximum acceptable baud rate
379 * Decode the termios structure into a numeric baud rate,
380 * taking account of the magic 38400 baud rate (with spd_*
381 * flags), and mapping the %B0 rate to 9600 baud.
383 * If the new baud rate is invalid, try the old termios setting.
384 * If it's still invalid, we try 9600 baud.
386 * Update the @termios structure to reflect the baud rate
387 * we're actually going to be using. Don't do this for the case
388 * where B0 is requested ("hang up").
391 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
392 struct ktermios *old, unsigned int min, unsigned int max)
396 unsigned int altbaud;
398 upf_t flags = port->flags & UPF_SPD_MASK;
418 for (try = 0; try < 2; try++) {
419 baud = tty_termios_baud_rate(termios);
422 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
425 if (try == 0 && baud == 38400)
429 * Special case: B0 rate.
436 if (baud >= min && baud <= max)
440 * Oops, the quotient was zero. Try again with
441 * the old baud rate if possible.
443 termios->c_cflag &= ~CBAUD;
445 baud = tty_termios_baud_rate(old);
447 tty_termios_encode_baud_rate(termios,
454 * As a last resort, if the range cannot be met then clip to
455 * the nearest chip supported rate.
459 tty_termios_encode_baud_rate(termios,
462 tty_termios_encode_baud_rate(termios,
466 /* Should never happen */
471 EXPORT_SYMBOL(uart_get_baud_rate);
474 * uart_get_divisor - return uart clock divisor
475 * @port: uart_port structure describing the port.
476 * @baud: desired baud rate
478 * Calculate the uart clock divisor for the port.
481 uart_get_divisor(struct uart_port *port, unsigned int baud)
486 * Old custom speed handling.
488 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
489 quot = port->custom_divisor;
491 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
496 EXPORT_SYMBOL(uart_get_divisor);
498 /* Caller holds port mutex */
499 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
500 struct ktermios *old_termios)
502 struct uart_port *uport = uart_port_check(state);
503 struct ktermios *termios;
507 * If we have no tty, termios, or the port does not exist,
508 * then we can't set the parameters for this port.
510 if (!tty || uport->type == PORT_UNKNOWN)
513 termios = &tty->termios;
514 uport->ops->set_termios(uport, termios, old_termios);
517 * Set modem status enables based on termios cflag
519 spin_lock_irq(&uport->lock);
520 if (termios->c_cflag & CRTSCTS)
521 uport->status |= UPSTAT_CTS_ENABLE;
523 uport->status &= ~UPSTAT_CTS_ENABLE;
525 if (termios->c_cflag & CLOCAL)
526 uport->status &= ~UPSTAT_DCD_ENABLE;
528 uport->status |= UPSTAT_DCD_ENABLE;
530 /* reset sw-assisted CTS flow control based on (possibly) new mode */
531 hw_stopped = uport->hw_stopped;
532 uport->hw_stopped = uart_softcts_mode(uport) &&
533 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
534 if (uport->hw_stopped) {
536 uport->ops->stop_tx(uport);
541 spin_unlock_irq(&uport->lock);
544 static int uart_put_char(struct tty_struct *tty, unsigned char c)
546 struct uart_state *state = tty->driver_data;
547 struct uart_port *port;
548 struct circ_buf *circ;
556 port = uart_port_lock(state, flags);
557 if (port && uart_circ_chars_free(circ) != 0) {
558 circ->buf[circ->head] = c;
559 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
562 uart_port_unlock(port, flags);
566 static void uart_flush_chars(struct tty_struct *tty)
571 static int uart_write(struct tty_struct *tty,
572 const unsigned char *buf, int count)
574 struct uart_state *state = tty->driver_data;
575 struct uart_port *port;
576 struct circ_buf *circ;
581 * This means you called this function _after_ the port was
582 * closed. No cookie for you.
593 port = uart_port_lock(state, flags);
595 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
600 memcpy(circ->buf + circ->head, buf, c);
601 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
608 uart_port_unlock(port, flags);
612 static int uart_write_room(struct tty_struct *tty)
614 struct uart_state *state = tty->driver_data;
615 struct uart_port *port;
619 port = uart_port_lock(state, flags);
620 ret = uart_circ_chars_free(&state->xmit);
621 uart_port_unlock(port, flags);
625 static int uart_chars_in_buffer(struct tty_struct *tty)
627 struct uart_state *state = tty->driver_data;
628 struct uart_port *port;
632 port = uart_port_lock(state, flags);
633 ret = uart_circ_chars_pending(&state->xmit);
634 uart_port_unlock(port, flags);
638 static void uart_flush_buffer(struct tty_struct *tty)
640 struct uart_state *state = tty->driver_data;
641 struct uart_port *port;
645 * This means you called this function _after_ the port was
646 * closed. No cookie for you.
653 pr_debug("uart_flush_buffer(%d) called\n", tty->index);
655 port = uart_port_lock(state, flags);
658 uart_circ_clear(&state->xmit);
659 if (port->ops->flush_buffer)
660 port->ops->flush_buffer(port);
661 uart_port_unlock(port, flags);
662 tty_port_tty_wakeup(&state->port);
666 * This function is used to send a high-priority XON/XOFF character to
669 static void uart_send_xchar(struct tty_struct *tty, char ch)
671 struct uart_state *state = tty->driver_data;
672 struct uart_port *port;
675 port = uart_port_ref(state);
679 if (port->ops->send_xchar)
680 port->ops->send_xchar(port, ch);
682 spin_lock_irqsave(&port->lock, flags);
685 port->ops->start_tx(port);
686 spin_unlock_irqrestore(&port->lock, flags);
688 uart_port_deref(port);
691 static void uart_throttle(struct tty_struct *tty)
693 struct uart_state *state = tty->driver_data;
694 upstat_t mask = UPSTAT_SYNC_FIFO;
695 struct uart_port *port;
697 port = uart_port_ref(state);
702 mask |= UPSTAT_AUTOXOFF;
704 mask |= UPSTAT_AUTORTS;
706 if (port->status & mask) {
707 port->ops->throttle(port);
708 mask &= ~port->status;
711 if (mask & UPSTAT_AUTORTS)
712 uart_clear_mctrl(port, TIOCM_RTS);
714 if (mask & UPSTAT_AUTOXOFF)
715 uart_send_xchar(tty, STOP_CHAR(tty));
717 uart_port_deref(port);
720 static void uart_unthrottle(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->unthrottle(port);
737 mask &= ~port->status;
740 if (mask & UPSTAT_AUTORTS)
741 uart_set_mctrl(port, TIOCM_RTS);
743 if (mask & UPSTAT_AUTOXOFF)
744 uart_send_xchar(tty, START_CHAR(tty));
746 uart_port_deref(port);
749 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
751 struct uart_state *state = container_of(port, struct uart_state, port);
752 struct uart_port *uport;
755 memset(retinfo, 0, sizeof(*retinfo));
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;
862 * Ask the low level driver to verify the settings.
864 if (uport->ops->verify_port)
865 retval = uport->ops->verify_port(uport, new_info);
867 if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
868 (new_info->baud_base < 9600))
874 if (change_port || change_irq) {
878 * Make sure that we are the sole user of this port.
880 if (tty_port_users(port) > 1)
884 * We need to shutdown the serial port at the old
885 * port/type/irq combination.
887 uart_shutdown(tty, state);
891 unsigned long old_iobase, old_mapbase;
892 unsigned int old_type, old_iotype, old_hub6, old_shift;
894 old_iobase = uport->iobase;
895 old_mapbase = uport->mapbase;
896 old_type = uport->type;
897 old_hub6 = uport->hub6;
898 old_iotype = uport->iotype;
899 old_shift = uport->regshift;
902 * Free and release old regions
904 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
905 uport->ops->release_port(uport);
907 uport->iobase = new_port;
908 uport->type = new_info->type;
909 uport->hub6 = new_info->hub6;
910 uport->iotype = new_info->io_type;
911 uport->regshift = new_info->iomem_reg_shift;
912 uport->mapbase = (unsigned long)new_info->iomem_base;
915 * Claim and map the new regions
917 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
918 retval = uport->ops->request_port(uport);
920 /* Always success - Jean II */
925 * If we fail to request resources for the
926 * new port, try to restore the old settings.
929 uport->iobase = old_iobase;
930 uport->type = old_type;
931 uport->hub6 = old_hub6;
932 uport->iotype = old_iotype;
933 uport->regshift = old_shift;
934 uport->mapbase = old_mapbase;
936 if (old_type != PORT_UNKNOWN) {
937 retval = uport->ops->request_port(uport);
939 * If we failed to restore the old settings,
943 uport->type = PORT_UNKNOWN;
951 /* Added to return the correct error -Ram Gupta */
957 uport->irq = new_info->irq;
958 if (!(uport->flags & UPF_FIXED_PORT))
959 uport->uartclk = new_info->baud_base * 16;
960 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
961 (new_flags & UPF_CHANGE_MASK);
962 uport->custom_divisor = new_info->custom_divisor;
963 port->close_delay = close_delay;
964 port->closing_wait = closing_wait;
965 if (new_info->xmit_fifo_size)
966 uport->fifosize = new_info->xmit_fifo_size;
967 port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
971 if (uport->type == PORT_UNKNOWN)
973 if (tty_port_initialized(port)) {
974 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
975 old_custom_divisor != uport->custom_divisor) {
977 * If they're setting up a custom divisor or speed,
978 * instead of clearing it, then bitch about it.
980 if (uport->flags & UPF_SPD_MASK) {
981 dev_notice_ratelimited(uport->dev,
982 "%s sets custom speed on %s. This is deprecated.\n",
984 tty_name(port->tty));
986 uart_change_speed(tty, state, NULL);
989 retval = uart_startup(tty, state, 1);
991 tty_port_set_initialized(port, true);
999 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1001 struct uart_state *state = tty->driver_data;
1002 struct tty_port *port = &state->port;
1005 down_write(&tty->termios_rwsem);
1007 * This semaphore protects port->count. It is also
1008 * very useful to prevent opens. Also, take the
1009 * port configuration semaphore to make sure that a
1010 * module insertion/removal doesn't change anything
1013 mutex_lock(&port->mutex);
1014 retval = uart_set_info(tty, port, state, ss);
1015 mutex_unlock(&port->mutex);
1016 up_write(&tty->termios_rwsem);
1021 * uart_get_lsr_info - get line status register info
1022 * @tty: tty associated with the UART
1023 * @state: UART being queried
1024 * @value: returned modem value
1026 static int uart_get_lsr_info(struct tty_struct *tty,
1027 struct uart_state *state, unsigned int __user *value)
1029 struct uart_port *uport = uart_port_check(state);
1030 unsigned int result;
1032 result = uport->ops->tx_empty(uport);
1035 * If we're about to load something into the transmit
1036 * register, we'll pretend the transmitter isn't empty to
1037 * avoid a race condition (depending on when the transmit
1038 * interrupt happens).
1040 if (uport->x_char ||
1041 ((uart_circ_chars_pending(&state->xmit) > 0) &&
1042 !uart_tx_stopped(uport)))
1043 result &= ~TIOCSER_TEMT;
1045 return put_user(result, value);
1048 static int uart_tiocmget(struct tty_struct *tty)
1050 struct uart_state *state = tty->driver_data;
1051 struct tty_port *port = &state->port;
1052 struct uart_port *uport;
1055 mutex_lock(&port->mutex);
1056 uport = uart_port_check(state);
1060 if (!tty_io_error(tty)) {
1061 result = uport->mctrl;
1062 spin_lock_irq(&uport->lock);
1063 result |= uport->ops->get_mctrl(uport);
1064 spin_unlock_irq(&uport->lock);
1067 mutex_unlock(&port->mutex);
1072 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1074 struct uart_state *state = tty->driver_data;
1075 struct tty_port *port = &state->port;
1076 struct uart_port *uport;
1079 mutex_lock(&port->mutex);
1080 uport = uart_port_check(state);
1084 if (!tty_io_error(tty)) {
1085 uart_update_mctrl(uport, set, clear);
1089 mutex_unlock(&port->mutex);
1093 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1095 struct uart_state *state = tty->driver_data;
1096 struct tty_port *port = &state->port;
1097 struct uart_port *uport;
1100 mutex_lock(&port->mutex);
1101 uport = uart_port_check(state);
1105 if (uport->type != PORT_UNKNOWN)
1106 uport->ops->break_ctl(uport, break_state);
1109 mutex_unlock(&port->mutex);
1113 static int uart_do_autoconfig(struct tty_struct *tty,struct uart_state *state)
1115 struct tty_port *port = &state->port;
1116 struct uart_port *uport;
1119 if (!capable(CAP_SYS_ADMIN))
1123 * Take the per-port semaphore. This prevents count from
1124 * changing, and hence any extra opens of the port while
1125 * we're auto-configuring.
1127 if (mutex_lock_interruptible(&port->mutex))
1128 return -ERESTARTSYS;
1130 uport = uart_port_check(state);
1137 if (tty_port_users(port) == 1) {
1138 uart_shutdown(tty, state);
1141 * If we already have a port type configured,
1142 * we must release its resources.
1144 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1145 uport->ops->release_port(uport);
1147 flags = UART_CONFIG_TYPE;
1148 if (uport->flags & UPF_AUTO_IRQ)
1149 flags |= UART_CONFIG_IRQ;
1152 * This will claim the ports resources if
1155 uport->ops->config_port(uport, flags);
1157 ret = uart_startup(tty, state, 1);
1159 tty_port_set_initialized(port, true);
1164 mutex_unlock(&port->mutex);
1168 static void uart_enable_ms(struct uart_port *uport)
1171 * Force modem status interrupts on
1173 if (uport->ops->enable_ms)
1174 uport->ops->enable_ms(uport);
1178 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1179 * - mask passed in arg for lines of interest
1180 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1181 * Caller should use TIOCGICOUNT to see which one it was
1183 * FIXME: This wants extracting into a common all driver implementation
1184 * of TIOCMWAIT using tty_port.
1186 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1188 struct uart_port *uport;
1189 struct tty_port *port = &state->port;
1190 DECLARE_WAITQUEUE(wait, current);
1191 struct uart_icount cprev, cnow;
1195 * note the counters on entry
1197 uport = uart_port_ref(state);
1200 spin_lock_irq(&uport->lock);
1201 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1202 uart_enable_ms(uport);
1203 spin_unlock_irq(&uport->lock);
1205 add_wait_queue(&port->delta_msr_wait, &wait);
1207 spin_lock_irq(&uport->lock);
1208 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1209 spin_unlock_irq(&uport->lock);
1211 set_current_state(TASK_INTERRUPTIBLE);
1213 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1214 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1215 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1216 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1223 /* see if a signal did it */
1224 if (signal_pending(current)) {
1231 __set_current_state(TASK_RUNNING);
1232 remove_wait_queue(&port->delta_msr_wait, &wait);
1233 uart_port_deref(uport);
1239 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1240 * Return: write counters to the user passed counter struct
1241 * NB: both 1->0 and 0->1 transitions are counted except for
1242 * RI where only 0->1 is counted.
1244 static int uart_get_icount(struct tty_struct *tty,
1245 struct serial_icounter_struct *icount)
1247 struct uart_state *state = tty->driver_data;
1248 struct uart_icount cnow;
1249 struct uart_port *uport;
1251 uport = uart_port_ref(state);
1254 spin_lock_irq(&uport->lock);
1255 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1256 spin_unlock_irq(&uport->lock);
1257 uart_port_deref(uport);
1259 icount->cts = cnow.cts;
1260 icount->dsr = cnow.dsr;
1261 icount->rng = cnow.rng;
1262 icount->dcd = cnow.dcd;
1263 icount->rx = cnow.rx;
1264 icount->tx = cnow.tx;
1265 icount->frame = cnow.frame;
1266 icount->overrun = cnow.overrun;
1267 icount->parity = cnow.parity;
1268 icount->brk = cnow.brk;
1269 icount->buf_overrun = cnow.buf_overrun;
1274 static int uart_get_rs485_config(struct uart_port *port,
1275 struct serial_rs485 __user *rs485)
1277 unsigned long flags;
1278 struct serial_rs485 aux;
1280 spin_lock_irqsave(&port->lock, flags);
1282 spin_unlock_irqrestore(&port->lock, flags);
1284 if (copy_to_user(rs485, &aux, sizeof(aux)))
1290 static int uart_set_rs485_config(struct uart_port *port,
1291 struct serial_rs485 __user *rs485_user)
1293 struct serial_rs485 rs485;
1295 unsigned long flags;
1297 if (!port->rs485_config)
1298 return -ENOIOCTLCMD;
1300 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1303 spin_lock_irqsave(&port->lock, flags);
1304 ret = port->rs485_config(port, &rs485);
1305 spin_unlock_irqrestore(&port->lock, flags);
1309 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1315 static int uart_get_iso7816_config(struct uart_port *port,
1316 struct serial_iso7816 __user *iso7816)
1318 unsigned long flags;
1319 struct serial_iso7816 aux;
1321 if (!port->iso7816_config)
1322 return -ENOIOCTLCMD;
1324 spin_lock_irqsave(&port->lock, flags);
1325 aux = port->iso7816;
1326 spin_unlock_irqrestore(&port->lock, flags);
1328 if (copy_to_user(iso7816, &aux, sizeof(aux)))
1334 static int uart_set_iso7816_config(struct uart_port *port,
1335 struct serial_iso7816 __user *iso7816_user)
1337 struct serial_iso7816 iso7816;
1339 unsigned long flags;
1341 if (!port->iso7816_config)
1342 return -ENOIOCTLCMD;
1344 if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1348 * There are 5 words reserved for future use. Check that userspace
1349 * doesn't put stuff in there to prevent breakages in the future.
1351 for (i = 0; i < 5; i++)
1352 if (iso7816.reserved[i])
1355 spin_lock_irqsave(&port->lock, flags);
1356 ret = port->iso7816_config(port, &iso7816);
1357 spin_unlock_irqrestore(&port->lock, flags);
1361 if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1368 * Called via sys_ioctl. We can use spin_lock_irq() here.
1371 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1373 struct uart_state *state = tty->driver_data;
1374 struct tty_port *port = &state->port;
1375 struct uart_port *uport;
1376 void __user *uarg = (void __user *)arg;
1377 int ret = -ENOIOCTLCMD;
1381 * These ioctls don't rely on the hardware to be present.
1385 down_write(&tty->termios_rwsem);
1386 ret = uart_do_autoconfig(tty, state);
1387 up_write(&tty->termios_rwsem);
1391 if (ret != -ENOIOCTLCMD)
1394 if (tty_io_error(tty)) {
1400 * The following should only be used when hardware is present.
1404 ret = uart_wait_modem_status(state, arg);
1408 if (ret != -ENOIOCTLCMD)
1411 mutex_lock(&port->mutex);
1412 uport = uart_port_check(state);
1414 if (!uport || tty_io_error(tty)) {
1420 * All these rely on hardware being present and need to be
1421 * protected against the tty being hung up.
1425 case TIOCSERGETLSR: /* Get line status register */
1426 ret = uart_get_lsr_info(tty, state, uarg);
1430 ret = uart_get_rs485_config(uport, uarg);
1434 ret = uart_set_rs485_config(uport, uarg);
1438 ret = uart_set_iso7816_config(state->uart_port, uarg);
1442 ret = uart_get_iso7816_config(state->uart_port, uarg);
1445 if (uport->ops->ioctl)
1446 ret = uport->ops->ioctl(uport, cmd, arg);
1450 mutex_unlock(&port->mutex);
1455 static void uart_set_ldisc(struct tty_struct *tty)
1457 struct uart_state *state = tty->driver_data;
1458 struct uart_port *uport;
1460 mutex_lock(&state->port.mutex);
1461 uport = uart_port_check(state);
1462 if (uport && uport->ops->set_ldisc)
1463 uport->ops->set_ldisc(uport, &tty->termios);
1464 mutex_unlock(&state->port.mutex);
1467 static void uart_set_termios(struct tty_struct *tty,
1468 struct ktermios *old_termios)
1470 struct uart_state *state = tty->driver_data;
1471 struct uart_port *uport;
1472 unsigned int cflag = tty->termios.c_cflag;
1473 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1474 bool sw_changed = false;
1476 mutex_lock(&state->port.mutex);
1477 uport = uart_port_check(state);
1482 * Drivers doing software flow control also need to know
1483 * about changes to these input settings.
1485 if (uport->flags & UPF_SOFT_FLOW) {
1486 iflag_mask |= IXANY|IXON|IXOFF;
1488 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1489 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1493 * These are the bits that are used to setup various
1494 * flags in the low level driver. We can ignore the Bfoo
1495 * bits in c_cflag; c_[io]speed will always be set
1496 * appropriately by set_termios() in tty_ioctl.c
1498 if ((cflag ^ old_termios->c_cflag) == 0 &&
1499 tty->termios.c_ospeed == old_termios->c_ospeed &&
1500 tty->termios.c_ispeed == old_termios->c_ispeed &&
1501 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1506 uart_change_speed(tty, state, old_termios);
1507 /* reload cflag from termios; port driver may have overriden flags */
1508 cflag = tty->termios.c_cflag;
1510 /* Handle transition to B0 status */
1511 if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1512 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1513 /* Handle transition away from B0 status */
1514 else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1515 unsigned int mask = TIOCM_DTR;
1516 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1518 uart_set_mctrl(uport, mask);
1521 mutex_unlock(&state->port.mutex);
1525 * Calls to uart_close() are serialised via the tty_lock in
1526 * drivers/tty/tty_io.c:tty_release()
1527 * drivers/tty/tty_io.c:do_tty_hangup()
1529 static void uart_close(struct tty_struct *tty, struct file *filp)
1531 struct uart_state *state = tty->driver_data;
1534 struct uart_driver *drv = tty->driver->driver_state;
1535 struct tty_port *port;
1537 state = drv->state + tty->index;
1538 port = &state->port;
1539 spin_lock_irq(&port->lock);
1541 spin_unlock_irq(&port->lock);
1545 pr_debug("uart_close(%d) called\n", tty->index);
1547 tty_port_close(tty->port, tty, filp);
1550 static void uart_tty_port_shutdown(struct tty_port *port)
1552 struct uart_state *state = container_of(port, struct uart_state, port);
1553 struct uart_port *uport = uart_port_check(state);
1556 * At this point, we stop accepting input. To do this, we
1557 * disable the receive line status interrupts.
1559 if (WARN(!uport, "detached port still initialized!\n"))
1562 spin_lock_irq(&uport->lock);
1563 uport->ops->stop_rx(uport);
1564 spin_unlock_irq(&uport->lock);
1566 uart_port_shutdown(port);
1569 * It's possible for shutdown to be called after suspend if we get
1570 * a DCD drop (hangup) at just the right time. Clear suspended bit so
1571 * we don't try to resume a port that has been shutdown.
1573 tty_port_set_suspended(port, 0);
1575 uart_change_pm(state, UART_PM_STATE_OFF);
1579 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1581 struct uart_state *state = tty->driver_data;
1582 struct uart_port *port;
1583 unsigned long char_time, expire;
1585 port = uart_port_ref(state);
1589 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1590 uart_port_deref(port);
1595 * Set the check interval to be 1/5 of the estimated time to
1596 * send a single character, and make it at least 1. The check
1597 * interval should also be less than the timeout.
1599 * Note: we have to use pretty tight timings here to satisfy
1602 char_time = (port->timeout - HZ/50) / port->fifosize;
1603 char_time = char_time / 5;
1606 if (timeout && timeout < char_time)
1607 char_time = timeout;
1610 * If the transmitter hasn't cleared in twice the approximate
1611 * amount of time to send the entire FIFO, it probably won't
1612 * ever clear. This assumes the UART isn't doing flow
1613 * control, which is currently the case. Hence, if it ever
1614 * takes longer than port->timeout, this is probably due to a
1615 * UART bug of some kind. So, we clamp the timeout parameter at
1618 if (timeout == 0 || timeout > 2 * port->timeout)
1619 timeout = 2 * port->timeout;
1621 expire = jiffies + timeout;
1623 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1624 port->line, jiffies, expire);
1627 * Check whether the transmitter is empty every 'char_time'.
1628 * 'timeout' / 'expire' give us the maximum amount of time
1631 while (!port->ops->tx_empty(port)) {
1632 msleep_interruptible(jiffies_to_msecs(char_time));
1633 if (signal_pending(current))
1635 if (time_after(jiffies, expire))
1638 uart_port_deref(port);
1642 * Calls to uart_hangup() are serialised by the tty_lock in
1643 * drivers/tty/tty_io.c:do_tty_hangup()
1644 * This runs from a workqueue and can sleep for a _short_ time only.
1646 static void uart_hangup(struct tty_struct *tty)
1648 struct uart_state *state = tty->driver_data;
1649 struct tty_port *port = &state->port;
1650 struct uart_port *uport;
1651 unsigned long flags;
1653 pr_debug("uart_hangup(%d)\n", tty->index);
1655 mutex_lock(&port->mutex);
1656 uport = uart_port_check(state);
1657 WARN(!uport, "hangup of detached port!\n");
1659 if (tty_port_active(port)) {
1660 uart_flush_buffer(tty);
1661 uart_shutdown(tty, state);
1662 spin_lock_irqsave(&port->lock, flags);
1664 spin_unlock_irqrestore(&port->lock, flags);
1665 tty_port_set_active(port, 0);
1666 tty_port_tty_set(port, NULL);
1667 if (uport && !uart_console(uport))
1668 uart_change_pm(state, UART_PM_STATE_OFF);
1669 wake_up_interruptible(&port->open_wait);
1670 wake_up_interruptible(&port->delta_msr_wait);
1672 mutex_unlock(&port->mutex);
1675 /* uport == NULL if uart_port has already been removed */
1676 static void uart_port_shutdown(struct tty_port *port)
1678 struct uart_state *state = container_of(port, struct uart_state, port);
1679 struct uart_port *uport = uart_port_check(state);
1682 * clear delta_msr_wait queue to avoid mem leaks: we may free
1683 * the irq here so the queue might never be woken up. Note
1684 * that we won't end up waiting on delta_msr_wait again since
1685 * any outstanding file descriptors should be pointing at
1686 * hung_up_tty_fops now.
1688 wake_up_interruptible(&port->delta_msr_wait);
1691 * Free the IRQ and disable the port.
1694 uport->ops->shutdown(uport);
1697 * Ensure that the IRQ handler isn't running on another CPU.
1700 synchronize_irq(uport->irq);
1703 static int uart_carrier_raised(struct tty_port *port)
1705 struct uart_state *state = container_of(port, struct uart_state, port);
1706 struct uart_port *uport;
1709 uport = uart_port_ref(state);
1711 * Should never observe uport == NULL since checks for hangup should
1712 * abort the tty_port_block_til_ready() loop before checking for carrier
1713 * raised -- but report carrier raised if it does anyway so open will
1714 * continue and not sleep
1716 if (WARN_ON(!uport))
1718 spin_lock_irq(&uport->lock);
1719 uart_enable_ms(uport);
1720 mctrl = uport->ops->get_mctrl(uport);
1721 spin_unlock_irq(&uport->lock);
1722 uart_port_deref(uport);
1723 if (mctrl & TIOCM_CAR)
1728 static void uart_dtr_rts(struct tty_port *port, int raise)
1730 struct uart_state *state = container_of(port, struct uart_state, port);
1731 struct uart_port *uport;
1733 uport = uart_port_ref(state);
1736 uart_port_dtr_rts(uport, raise);
1737 uart_port_deref(uport);
1741 * Calls to uart_open are serialised by the tty_lock in
1742 * drivers/tty/tty_io.c:tty_open()
1743 * Note that if this fails, then uart_close() _will_ be called.
1745 * In time, we want to scrap the "opening nonpresent ports"
1746 * behaviour and implement an alternative way for setserial
1747 * to set base addresses/ports/types. This will allow us to
1748 * get rid of a certain amount of extra tests.
1750 static int uart_open(struct tty_struct *tty, struct file *filp)
1752 struct uart_driver *drv = tty->driver->driver_state;
1753 int retval, line = tty->index;
1754 struct uart_state *state = drv->state + line;
1756 tty->driver_data = state;
1758 retval = tty_port_open(&state->port, tty, filp);
1765 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1767 struct uart_state *state = container_of(port, struct uart_state, port);
1768 struct uart_port *uport;
1770 uport = uart_port_check(state);
1771 if (!uport || uport->flags & UPF_DEAD)
1774 port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
1777 * Start up the serial port.
1779 return uart_startup(tty, state, 0);
1782 static const char *uart_type(struct uart_port *port)
1784 const char *str = NULL;
1786 if (port->ops->type)
1787 str = port->ops->type(port);
1795 #ifdef CONFIG_PROC_FS
1797 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1799 struct uart_state *state = drv->state + i;
1800 struct tty_port *port = &state->port;
1801 enum uart_pm_state pm_state;
1802 struct uart_port *uport;
1804 unsigned int status;
1807 mutex_lock(&port->mutex);
1808 uport = uart_port_check(state);
1812 mmio = uport->iotype >= UPIO_MEM;
1813 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
1814 uport->line, uart_type(uport),
1815 mmio ? "mmio:0x" : "port:",
1816 mmio ? (unsigned long long)uport->mapbase
1817 : (unsigned long long)uport->iobase,
1820 if (uport->type == PORT_UNKNOWN) {
1825 if (capable(CAP_SYS_ADMIN)) {
1826 pm_state = state->pm_state;
1827 if (pm_state != UART_PM_STATE_ON)
1828 uart_change_pm(state, UART_PM_STATE_ON);
1829 spin_lock_irq(&uport->lock);
1830 status = uport->ops->get_mctrl(uport);
1831 spin_unlock_irq(&uport->lock);
1832 if (pm_state != UART_PM_STATE_ON)
1833 uart_change_pm(state, pm_state);
1835 seq_printf(m, " tx:%d rx:%d",
1836 uport->icount.tx, uport->icount.rx);
1837 if (uport->icount.frame)
1838 seq_printf(m, " fe:%d", uport->icount.frame);
1839 if (uport->icount.parity)
1840 seq_printf(m, " pe:%d", uport->icount.parity);
1841 if (uport->icount.brk)
1842 seq_printf(m, " brk:%d", uport->icount.brk);
1843 if (uport->icount.overrun)
1844 seq_printf(m, " oe:%d", uport->icount.overrun);
1845 if (uport->icount.buf_overrun)
1846 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
1848 #define INFOBIT(bit, str) \
1849 if (uport->mctrl & (bit)) \
1850 strncat(stat_buf, (str), sizeof(stat_buf) - \
1851 strlen(stat_buf) - 2)
1852 #define STATBIT(bit, str) \
1853 if (status & (bit)) \
1854 strncat(stat_buf, (str), sizeof(stat_buf) - \
1855 strlen(stat_buf) - 2)
1859 INFOBIT(TIOCM_RTS, "|RTS");
1860 STATBIT(TIOCM_CTS, "|CTS");
1861 INFOBIT(TIOCM_DTR, "|DTR");
1862 STATBIT(TIOCM_DSR, "|DSR");
1863 STATBIT(TIOCM_CAR, "|CD");
1864 STATBIT(TIOCM_RNG, "|RI");
1868 seq_puts(m, stat_buf);
1874 mutex_unlock(&port->mutex);
1877 static int uart_proc_show(struct seq_file *m, void *v)
1879 struct tty_driver *ttydrv = m->private;
1880 struct uart_driver *drv = ttydrv->driver_state;
1883 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
1884 for (i = 0; i < drv->nr; i++)
1885 uart_line_info(m, drv, i);
1890 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
1892 * uart_console_write - write a console message to a serial port
1893 * @port: the port to write the message
1894 * @s: array of characters
1895 * @count: number of characters in string to write
1896 * @putchar: function to write character to port
1898 void uart_console_write(struct uart_port *port, const char *s,
1900 void (*putchar)(struct uart_port *, int))
1904 for (i = 0; i < count; i++, s++) {
1906 putchar(port, '\r');
1910 EXPORT_SYMBOL_GPL(uart_console_write);
1913 * Check whether an invalid uart number has been specified, and
1914 * if so, search for the first available port that does have
1917 struct uart_port * __init
1918 uart_get_console(struct uart_port *ports, int nr, struct console *co)
1920 int idx = co->index;
1922 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1923 ports[idx].membase == NULL))
1924 for (idx = 0; idx < nr; idx++)
1925 if (ports[idx].iobase != 0 ||
1926 ports[idx].membase != NULL)
1935 * uart_parse_earlycon - Parse earlycon options
1936 * @p: ptr to 2nd field (ie., just beyond '<name>,')
1937 * @iotype: ptr for decoded iotype (out)
1938 * @addr: ptr for decoded mapbase/iobase (out)
1939 * @options: ptr for <options> field; NULL if not present (out)
1941 * Decodes earlycon kernel command line parameters of the form
1942 * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1943 * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1946 * earlycon=<name>,0x<addr>,<options>
1947 * console=<name>,0x<addr>,<options>
1948 * is also accepted; the returned @iotype will be UPIO_MEM.
1950 * Returns 0 on success or -EINVAL on failure
1952 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
1955 if (strncmp(p, "mmio,", 5) == 0) {
1958 } else if (strncmp(p, "mmio16,", 7) == 0) {
1959 *iotype = UPIO_MEM16;
1961 } else if (strncmp(p, "mmio32,", 7) == 0) {
1962 *iotype = UPIO_MEM32;
1964 } else if (strncmp(p, "mmio32be,", 9) == 0) {
1965 *iotype = UPIO_MEM32BE;
1967 } else if (strncmp(p, "mmio32native,", 13) == 0) {
1968 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
1969 UPIO_MEM32BE : UPIO_MEM32;
1971 } else if (strncmp(p, "io,", 3) == 0) {
1972 *iotype = UPIO_PORT;
1974 } else if (strncmp(p, "0x", 2) == 0) {
1981 * Before you replace it with kstrtoull(), think about options separator
1982 * (',') it will not tolerate
1984 *addr = simple_strtoull(p, NULL, 0);
1992 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
1995 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
1996 * @options: pointer to option string
1997 * @baud: pointer to an 'int' variable for the baud rate.
1998 * @parity: pointer to an 'int' variable for the parity.
1999 * @bits: pointer to an 'int' variable for the number of data bits.
2000 * @flow: pointer to an 'int' variable for the flow control character.
2002 * uart_parse_options decodes a string containing the serial console
2003 * options. The format of the string is <baud><parity><bits><flow>,
2007 uart_parse_options(const char *options, int *baud, int *parity,
2008 int *bits, int *flow)
2010 const char *s = options;
2012 *baud = simple_strtoul(s, NULL, 10);
2013 while (*s >= '0' && *s <= '9')
2022 EXPORT_SYMBOL_GPL(uart_parse_options);
2025 * uart_set_options - setup the serial console parameters
2026 * @port: pointer to the serial ports uart_port structure
2027 * @co: console pointer
2029 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2030 * @bits: number of data bits
2031 * @flow: flow control character - 'r' (rts)
2034 uart_set_options(struct uart_port *port, struct console *co,
2035 int baud, int parity, int bits, int flow)
2037 struct ktermios termios;
2038 static struct ktermios dummy;
2041 * Ensure that the serial console lock is initialised
2043 * If this port is a console, then the spinlock is already
2046 if (!(uart_console(port) && (port->cons->flags & CON_ENABLED))) {
2047 spin_lock_init(&port->lock);
2048 lockdep_set_class(&port->lock, &port_lock_key);
2051 memset(&termios, 0, sizeof(struct ktermios));
2053 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2054 tty_termios_encode_baud_rate(&termios, baud, baud);
2057 termios.c_cflag |= CS7;
2059 termios.c_cflag |= CS8;
2063 termios.c_cflag |= PARODD;
2066 termios.c_cflag |= PARENB;
2071 termios.c_cflag |= CRTSCTS;
2074 * some uarts on other side don't support no flow control.
2075 * So we set * DTR in host uart to make them happy
2077 port->mctrl |= TIOCM_DTR;
2079 port->ops->set_termios(port, &termios, &dummy);
2081 * Allow the setting of the UART parameters with a NULL console
2085 co->cflag = termios.c_cflag;
2089 EXPORT_SYMBOL_GPL(uart_set_options);
2090 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2093 * uart_change_pm - set power state of the port
2095 * @state: port descriptor
2096 * @pm_state: new state
2098 * Locking: port->mutex has to be held
2100 static void uart_change_pm(struct uart_state *state,
2101 enum uart_pm_state pm_state)
2103 struct uart_port *port = uart_port_check(state);
2105 if (state->pm_state != pm_state) {
2106 if (port && port->ops->pm)
2107 port->ops->pm(port, pm_state, state->pm_state);
2108 state->pm_state = pm_state;
2113 struct uart_port *port;
2114 struct uart_driver *driver;
2117 static int serial_match_port(struct device *dev, void *data)
2119 struct uart_match *match = data;
2120 struct tty_driver *tty_drv = match->driver->tty_driver;
2121 dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2124 return dev->devt == devt; /* Actually, only one tty per port */
2127 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2129 struct uart_state *state = drv->state + uport->line;
2130 struct tty_port *port = &state->port;
2131 struct device *tty_dev;
2132 struct uart_match match = {uport, drv};
2134 mutex_lock(&port->mutex);
2136 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2137 if (tty_dev && device_may_wakeup(tty_dev)) {
2138 enable_irq_wake(uport->irq);
2139 put_device(tty_dev);
2140 mutex_unlock(&port->mutex);
2143 put_device(tty_dev);
2145 /* Nothing to do if the console is not suspending */
2146 if (!console_suspend_enabled && uart_console(uport))
2149 uport->suspended = 1;
2151 if (tty_port_initialized(port)) {
2152 const struct uart_ops *ops = uport->ops;
2155 tty_port_set_suspended(port, 1);
2156 tty_port_set_initialized(port, 0);
2158 spin_lock_irq(&uport->lock);
2159 ops->stop_tx(uport);
2160 ops->set_mctrl(uport, 0);
2161 ops->stop_rx(uport);
2162 spin_unlock_irq(&uport->lock);
2165 * Wait for the transmitter to empty.
2167 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2170 dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2173 ops->shutdown(uport);
2177 * Disable the console device before suspending.
2179 if (uart_console(uport))
2180 console_stop(uport->cons);
2182 uart_change_pm(state, UART_PM_STATE_OFF);
2184 mutex_unlock(&port->mutex);
2189 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2191 struct uart_state *state = drv->state + uport->line;
2192 struct tty_port *port = &state->port;
2193 struct device *tty_dev;
2194 struct uart_match match = {uport, drv};
2195 struct ktermios termios;
2197 mutex_lock(&port->mutex);
2199 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2200 if (!uport->suspended && device_may_wakeup(tty_dev)) {
2201 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2202 disable_irq_wake(uport->irq);
2203 put_device(tty_dev);
2204 mutex_unlock(&port->mutex);
2207 put_device(tty_dev);
2208 uport->suspended = 0;
2211 * Re-enable the console device after suspending.
2213 if (uart_console(uport)) {
2215 * First try to use the console cflag setting.
2217 memset(&termios, 0, sizeof(struct ktermios));
2218 termios.c_cflag = uport->cons->cflag;
2221 * If that's unset, use the tty termios setting.
2223 if (port->tty && termios.c_cflag == 0)
2224 termios = port->tty->termios;
2226 if (console_suspend_enabled)
2227 uart_change_pm(state, UART_PM_STATE_ON);
2228 uport->ops->set_termios(uport, &termios, NULL);
2229 if (console_suspend_enabled)
2230 console_start(uport->cons);
2233 if (tty_port_suspended(port)) {
2234 const struct uart_ops *ops = uport->ops;
2237 uart_change_pm(state, UART_PM_STATE_ON);
2238 spin_lock_irq(&uport->lock);
2239 ops->set_mctrl(uport, 0);
2240 spin_unlock_irq(&uport->lock);
2241 if (console_suspend_enabled || !uart_console(uport)) {
2242 /* Protected by port mutex for now */
2243 struct tty_struct *tty = port->tty;
2244 ret = ops->startup(uport);
2247 uart_change_speed(tty, state, NULL);
2248 spin_lock_irq(&uport->lock);
2249 ops->set_mctrl(uport, uport->mctrl);
2250 ops->start_tx(uport);
2251 spin_unlock_irq(&uport->lock);
2252 tty_port_set_initialized(port, 1);
2255 * Failed to resume - maybe hardware went away?
2256 * Clear the "initialized" flag so we won't try
2257 * to call the low level drivers shutdown method.
2259 uart_shutdown(tty, state);
2263 tty_port_set_suspended(port, 0);
2266 mutex_unlock(&port->mutex);
2272 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2276 switch (port->iotype) {
2278 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2281 snprintf(address, sizeof(address),
2282 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2290 snprintf(address, sizeof(address),
2291 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2294 strlcpy(address, "*unknown*", sizeof(address));
2298 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2299 port->dev ? dev_name(port->dev) : "",
2300 port->dev ? ": " : "",
2302 address, port->irq, port->uartclk / 16, uart_type(port));
2306 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2307 struct uart_port *port)
2312 * If there isn't a port here, don't do anything further.
2314 if (!port->iobase && !port->mapbase && !port->membase)
2318 * Now do the auto configuration stuff. Note that config_port
2319 * is expected to claim the resources and map the port for us.
2322 if (port->flags & UPF_AUTO_IRQ)
2323 flags |= UART_CONFIG_IRQ;
2324 if (port->flags & UPF_BOOT_AUTOCONF) {
2325 if (!(port->flags & UPF_FIXED_TYPE)) {
2326 port->type = PORT_UNKNOWN;
2327 flags |= UART_CONFIG_TYPE;
2329 port->ops->config_port(port, flags);
2332 if (port->type != PORT_UNKNOWN) {
2333 unsigned long flags;
2335 uart_report_port(drv, port);
2337 /* Power up port for set_mctrl() */
2338 uart_change_pm(state, UART_PM_STATE_ON);
2341 * Ensure that the modem control lines are de-activated.
2342 * keep the DTR setting that is set in uart_set_options()
2343 * We probably don't need a spinlock around this, but
2345 spin_lock_irqsave(&port->lock, flags);
2346 port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
2347 spin_unlock_irqrestore(&port->lock, flags);
2350 * If this driver supports console, and it hasn't been
2351 * successfully registered yet, try to re-register it.
2352 * It may be that the port was not available.
2354 if (port->cons && !(port->cons->flags & CON_ENABLED))
2355 register_console(port->cons);
2358 * Power down all ports by default, except the
2359 * console if we have one.
2361 if (!uart_console(port))
2362 uart_change_pm(state, UART_PM_STATE_OFF);
2366 #ifdef CONFIG_CONSOLE_POLL
2368 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2370 struct uart_driver *drv = driver->driver_state;
2371 struct uart_state *state = drv->state + line;
2372 struct tty_port *tport;
2373 struct uart_port *port;
2380 tport = &state->port;
2381 mutex_lock(&tport->mutex);
2383 port = uart_port_check(state);
2384 if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2389 if (port->ops->poll_init) {
2391 * We don't set initialized as we only initialized the hw,
2392 * e.g. state->xmit is still uninitialized.
2394 if (!tty_port_initialized(tport))
2395 ret = port->ops->poll_init(port);
2398 if (!ret && options) {
2399 uart_parse_options(options, &baud, &parity, &bits, &flow);
2400 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2403 mutex_unlock(&tport->mutex);
2407 static int uart_poll_get_char(struct tty_driver *driver, int line)
2409 struct uart_driver *drv = driver->driver_state;
2410 struct uart_state *state = drv->state + line;
2411 struct uart_port *port;
2414 port = uart_port_ref(state);
2416 ret = port->ops->poll_get_char(port);
2417 uart_port_deref(port);
2423 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2425 struct uart_driver *drv = driver->driver_state;
2426 struct uart_state *state = drv->state + line;
2427 struct uart_port *port;
2429 port = uart_port_ref(state);
2434 port->ops->poll_put_char(port, '\r');
2435 port->ops->poll_put_char(port, ch);
2436 uart_port_deref(port);
2440 static const struct tty_operations uart_ops = {
2442 .close = uart_close,
2443 .write = uart_write,
2444 .put_char = uart_put_char,
2445 .flush_chars = uart_flush_chars,
2446 .write_room = uart_write_room,
2447 .chars_in_buffer= uart_chars_in_buffer,
2448 .flush_buffer = uart_flush_buffer,
2449 .ioctl = uart_ioctl,
2450 .throttle = uart_throttle,
2451 .unthrottle = uart_unthrottle,
2452 .send_xchar = uart_send_xchar,
2453 .set_termios = uart_set_termios,
2454 .set_ldisc = uart_set_ldisc,
2456 .start = uart_start,
2457 .hangup = uart_hangup,
2458 .break_ctl = uart_break_ctl,
2459 .wait_until_sent= uart_wait_until_sent,
2460 #ifdef CONFIG_PROC_FS
2461 .proc_show = uart_proc_show,
2463 .tiocmget = uart_tiocmget,
2464 .tiocmset = uart_tiocmset,
2465 .set_serial = uart_set_info_user,
2466 .get_serial = uart_get_info_user,
2467 .get_icount = uart_get_icount,
2468 #ifdef CONFIG_CONSOLE_POLL
2469 .poll_init = uart_poll_init,
2470 .poll_get_char = uart_poll_get_char,
2471 .poll_put_char = uart_poll_put_char,
2475 static const struct tty_port_operations uart_port_ops = {
2476 .carrier_raised = uart_carrier_raised,
2477 .dtr_rts = uart_dtr_rts,
2478 .activate = uart_port_activate,
2479 .shutdown = uart_tty_port_shutdown,
2483 * uart_register_driver - register a driver with the uart core layer
2484 * @drv: low level driver structure
2486 * Register a uart driver with the core driver. We in turn register
2487 * with the tty layer, and initialise the core driver per-port state.
2489 * We have a proc file in /proc/tty/driver which is named after the
2492 * drv->port should be NULL, and the per-port structures should be
2493 * registered using uart_add_one_port after this call has succeeded.
2495 int uart_register_driver(struct uart_driver *drv)
2497 struct tty_driver *normal;
2503 * Maybe we should be using a slab cache for this, especially if
2504 * we have a large number of ports to handle.
2506 drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2510 normal = alloc_tty_driver(drv->nr);
2514 drv->tty_driver = normal;
2516 normal->driver_name = drv->driver_name;
2517 normal->name = drv->dev_name;
2518 normal->major = drv->major;
2519 normal->minor_start = drv->minor;
2520 normal->type = TTY_DRIVER_TYPE_SERIAL;
2521 normal->subtype = SERIAL_TYPE_NORMAL;
2522 normal->init_termios = tty_std_termios;
2523 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2524 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2525 normal->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
2526 normal->driver_state = drv;
2527 tty_set_operations(normal, &uart_ops);
2530 * Initialise the UART state(s).
2532 for (i = 0; i < drv->nr; i++) {
2533 struct uart_state *state = drv->state + i;
2534 struct tty_port *port = &state->port;
2536 tty_port_init(port);
2537 port->ops = &uart_port_ops;
2540 retval = tty_register_driver(normal);
2544 for (i = 0; i < drv->nr; i++)
2545 tty_port_destroy(&drv->state[i].port);
2546 put_tty_driver(normal);
2554 * uart_unregister_driver - remove a driver from the uart core layer
2555 * @drv: low level driver structure
2557 * Remove all references to a driver from the core driver. The low
2558 * level driver must have removed all its ports via the
2559 * uart_remove_one_port() if it registered them with uart_add_one_port().
2560 * (ie, drv->port == NULL)
2562 void uart_unregister_driver(struct uart_driver *drv)
2564 struct tty_driver *p = drv->tty_driver;
2567 tty_unregister_driver(p);
2569 for (i = 0; i < drv->nr; i++)
2570 tty_port_destroy(&drv->state[i].port);
2573 drv->tty_driver = NULL;
2576 struct tty_driver *uart_console_device(struct console *co, int *index)
2578 struct uart_driver *p = co->data;
2580 return p->tty_driver;
2583 static ssize_t uart_get_attr_uartclk(struct device *dev,
2584 struct device_attribute *attr, char *buf)
2586 struct serial_struct tmp;
2587 struct tty_port *port = dev_get_drvdata(dev);
2589 uart_get_info(port, &tmp);
2590 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.baud_base * 16);
2593 static ssize_t uart_get_attr_type(struct device *dev,
2594 struct device_attribute *attr, char *buf)
2596 struct serial_struct tmp;
2597 struct tty_port *port = dev_get_drvdata(dev);
2599 uart_get_info(port, &tmp);
2600 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.type);
2602 static ssize_t uart_get_attr_line(struct device *dev,
2603 struct device_attribute *attr, char *buf)
2605 struct serial_struct tmp;
2606 struct tty_port *port = dev_get_drvdata(dev);
2608 uart_get_info(port, &tmp);
2609 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.line);
2612 static ssize_t uart_get_attr_port(struct device *dev,
2613 struct device_attribute *attr, char *buf)
2615 struct serial_struct tmp;
2616 struct tty_port *port = dev_get_drvdata(dev);
2617 unsigned long ioaddr;
2619 uart_get_info(port, &tmp);
2621 if (HIGH_BITS_OFFSET)
2622 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2623 return snprintf(buf, PAGE_SIZE, "0x%lX\n", ioaddr);
2626 static ssize_t uart_get_attr_irq(struct device *dev,
2627 struct device_attribute *attr, char *buf)
2629 struct serial_struct tmp;
2630 struct tty_port *port = dev_get_drvdata(dev);
2632 uart_get_info(port, &tmp);
2633 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.irq);
2636 static ssize_t uart_get_attr_flags(struct device *dev,
2637 struct device_attribute *attr, char *buf)
2639 struct serial_struct tmp;
2640 struct tty_port *port = dev_get_drvdata(dev);
2642 uart_get_info(port, &tmp);
2643 return snprintf(buf, PAGE_SIZE, "0x%X\n", tmp.flags);
2646 static ssize_t uart_get_attr_xmit_fifo_size(struct device *dev,
2647 struct device_attribute *attr, char *buf)
2649 struct serial_struct tmp;
2650 struct tty_port *port = dev_get_drvdata(dev);
2652 uart_get_info(port, &tmp);
2653 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.xmit_fifo_size);
2657 static ssize_t uart_get_attr_close_delay(struct device *dev,
2658 struct device_attribute *attr, char *buf)
2660 struct serial_struct tmp;
2661 struct tty_port *port = dev_get_drvdata(dev);
2663 uart_get_info(port, &tmp);
2664 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.close_delay);
2668 static ssize_t uart_get_attr_closing_wait(struct device *dev,
2669 struct device_attribute *attr, char *buf)
2671 struct serial_struct tmp;
2672 struct tty_port *port = dev_get_drvdata(dev);
2674 uart_get_info(port, &tmp);
2675 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.closing_wait);
2678 static ssize_t uart_get_attr_custom_divisor(struct device *dev,
2679 struct device_attribute *attr, char *buf)
2681 struct serial_struct tmp;
2682 struct tty_port *port = dev_get_drvdata(dev);
2684 uart_get_info(port, &tmp);
2685 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.custom_divisor);
2688 static ssize_t uart_get_attr_io_type(struct device *dev,
2689 struct device_attribute *attr, char *buf)
2691 struct serial_struct tmp;
2692 struct tty_port *port = dev_get_drvdata(dev);
2694 uart_get_info(port, &tmp);
2695 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.io_type);
2698 static ssize_t uart_get_attr_iomem_base(struct device *dev,
2699 struct device_attribute *attr, char *buf)
2701 struct serial_struct tmp;
2702 struct tty_port *port = dev_get_drvdata(dev);
2704 uart_get_info(port, &tmp);
2705 return snprintf(buf, PAGE_SIZE, "0x%lX\n", (unsigned long)tmp.iomem_base);
2708 static ssize_t uart_get_attr_iomem_reg_shift(struct device *dev,
2709 struct device_attribute *attr, char *buf)
2711 struct serial_struct tmp;
2712 struct tty_port *port = dev_get_drvdata(dev);
2714 uart_get_info(port, &tmp);
2715 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.iomem_reg_shift);
2718 static DEVICE_ATTR(type, S_IRUSR | S_IRGRP, uart_get_attr_type, NULL);
2719 static DEVICE_ATTR(line, S_IRUSR | S_IRGRP, uart_get_attr_line, NULL);
2720 static DEVICE_ATTR(port, S_IRUSR | S_IRGRP, uart_get_attr_port, NULL);
2721 static DEVICE_ATTR(irq, S_IRUSR | S_IRGRP, uart_get_attr_irq, NULL);
2722 static DEVICE_ATTR(flags, S_IRUSR | S_IRGRP, uart_get_attr_flags, NULL);
2723 static DEVICE_ATTR(xmit_fifo_size, S_IRUSR | S_IRGRP, uart_get_attr_xmit_fifo_size, NULL);
2724 static DEVICE_ATTR(uartclk, S_IRUSR | S_IRGRP, uart_get_attr_uartclk, NULL);
2725 static DEVICE_ATTR(close_delay, S_IRUSR | S_IRGRP, uart_get_attr_close_delay, NULL);
2726 static DEVICE_ATTR(closing_wait, S_IRUSR | S_IRGRP, uart_get_attr_closing_wait, NULL);
2727 static DEVICE_ATTR(custom_divisor, S_IRUSR | S_IRGRP, uart_get_attr_custom_divisor, NULL);
2728 static DEVICE_ATTR(io_type, S_IRUSR | S_IRGRP, uart_get_attr_io_type, NULL);
2729 static DEVICE_ATTR(iomem_base, S_IRUSR | S_IRGRP, uart_get_attr_iomem_base, NULL);
2730 static DEVICE_ATTR(iomem_reg_shift, S_IRUSR | S_IRGRP, uart_get_attr_iomem_reg_shift, NULL);
2732 static struct attribute *tty_dev_attrs[] = {
2733 &dev_attr_type.attr,
2734 &dev_attr_line.attr,
2735 &dev_attr_port.attr,
2737 &dev_attr_flags.attr,
2738 &dev_attr_xmit_fifo_size.attr,
2739 &dev_attr_uartclk.attr,
2740 &dev_attr_close_delay.attr,
2741 &dev_attr_closing_wait.attr,
2742 &dev_attr_custom_divisor.attr,
2743 &dev_attr_io_type.attr,
2744 &dev_attr_iomem_base.attr,
2745 &dev_attr_iomem_reg_shift.attr,
2749 static const struct attribute_group tty_dev_attr_group = {
2750 .attrs = tty_dev_attrs,
2754 * uart_add_one_port - attach a driver-defined port structure
2755 * @drv: pointer to the uart low level driver structure for this port
2756 * @uport: uart port structure to use for this port.
2758 * This allows the driver to register its own uart_port structure
2759 * with the core driver. The main purpose is to allow the low
2760 * level uart drivers to expand uart_port, rather than having yet
2761 * more levels of structures.
2763 int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
2765 struct uart_state *state;
2766 struct tty_port *port;
2768 struct device *tty_dev;
2771 BUG_ON(in_interrupt());
2773 if (uport->line >= drv->nr)
2776 state = drv->state + uport->line;
2777 port = &state->port;
2779 mutex_lock(&port_mutex);
2780 mutex_lock(&port->mutex);
2781 if (state->uart_port) {
2786 /* Link the port to the driver state table and vice versa */
2787 atomic_set(&state->refcount, 1);
2788 init_waitqueue_head(&state->remove_wait);
2789 state->uart_port = uport;
2790 uport->state = state;
2792 state->pm_state = UART_PM_STATE_UNDEFINED;
2793 uport->cons = drv->cons;
2794 uport->minor = drv->tty_driver->minor_start + uport->line;
2795 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
2796 drv->tty_driver->name_base + uport->line);
2803 * If this port is a console, then the spinlock is already
2806 if (!(uart_console(uport) && (uport->cons->flags & CON_ENABLED))) {
2807 spin_lock_init(&uport->lock);
2808 lockdep_set_class(&uport->lock, &port_lock_key);
2810 if (uport->cons && uport->dev)
2811 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
2813 uart_configure_port(drv, state, uport);
2815 port->console = uart_console(uport);
2818 if (uport->attr_group)
2821 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
2823 if (!uport->tty_groups) {
2827 uport->tty_groups[0] = &tty_dev_attr_group;
2828 if (uport->attr_group)
2829 uport->tty_groups[1] = uport->attr_group;
2832 * Register the port whether it's detected or not. This allows
2833 * setserial to be used to alter this port's parameters.
2835 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
2836 uport->line, uport->dev, port, uport->tty_groups);
2837 if (likely(!IS_ERR(tty_dev))) {
2838 device_set_wakeup_capable(tty_dev, 1);
2840 dev_err(uport->dev, "Cannot register tty device on line %d\n",
2845 * Ensure UPF_DEAD is not set.
2847 uport->flags &= ~UPF_DEAD;
2850 mutex_unlock(&port->mutex);
2851 mutex_unlock(&port_mutex);
2857 * uart_remove_one_port - detach a driver defined port structure
2858 * @drv: pointer to the uart low level driver structure for this port
2859 * @uport: uart port structure for this port
2861 * This unhooks (and hangs up) the specified port structure from the
2862 * core driver. No further calls will be made to the low-level code
2865 int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
2867 struct uart_state *state = drv->state + uport->line;
2868 struct tty_port *port = &state->port;
2869 struct uart_port *uart_port;
2870 struct tty_struct *tty;
2873 BUG_ON(in_interrupt());
2875 mutex_lock(&port_mutex);
2878 * Mark the port "dead" - this prevents any opens from
2879 * succeeding while we shut down the port.
2881 mutex_lock(&port->mutex);
2882 uart_port = uart_port_check(state);
2883 if (uart_port != uport)
2884 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
2888 mutex_unlock(&port->mutex);
2892 uport->flags |= UPF_DEAD;
2893 mutex_unlock(&port->mutex);
2896 * Remove the devices from the tty layer
2898 tty_port_unregister_device(port, drv->tty_driver, uport->line);
2900 tty = tty_port_tty_get(port);
2902 tty_vhangup(port->tty);
2907 * If the port is used as a console, unregister it
2909 if (uart_console(uport))
2910 unregister_console(uport->cons);
2913 * Free the port IO and memory resources, if any.
2915 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
2916 uport->ops->release_port(uport);
2917 kfree(uport->tty_groups);
2921 * Indicate that there isn't a port here anymore.
2923 uport->type = PORT_UNKNOWN;
2925 mutex_lock(&port->mutex);
2926 WARN_ON(atomic_dec_return(&state->refcount) < 0);
2927 wait_event(state->remove_wait, !atomic_read(&state->refcount));
2928 state->uart_port = NULL;
2929 mutex_unlock(&port->mutex);
2931 mutex_unlock(&port_mutex);
2937 * Are the two ports equivalent?
2939 int uart_match_port(struct uart_port *port1, struct uart_port *port2)
2941 if (port1->iotype != port2->iotype)
2944 switch (port1->iotype) {
2946 return (port1->iobase == port2->iobase);
2948 return (port1->iobase == port2->iobase) &&
2949 (port1->hub6 == port2->hub6);
2956 return (port1->mapbase == port2->mapbase);
2960 EXPORT_SYMBOL(uart_match_port);
2963 * uart_handle_dcd_change - handle a change of carrier detect state
2964 * @uport: uart_port structure for the open port
2965 * @status: new carrier detect status, nonzero if active
2967 * Caller must hold uport->lock
2969 void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
2971 struct tty_port *port = &uport->state->port;
2972 struct tty_struct *tty = port->tty;
2973 struct tty_ldisc *ld;
2975 lockdep_assert_held_once(&uport->lock);
2978 ld = tty_ldisc_ref(tty);
2980 if (ld->ops->dcd_change)
2981 ld->ops->dcd_change(tty, status);
2982 tty_ldisc_deref(ld);
2986 uport->icount.dcd++;
2988 if (uart_dcd_enabled(uport)) {
2990 wake_up_interruptible(&port->open_wait);
2995 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
2998 * uart_handle_cts_change - handle a change of clear-to-send state
2999 * @uport: uart_port structure for the open port
3000 * @status: new clear to send status, nonzero if active
3002 * Caller must hold uport->lock
3004 void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
3006 lockdep_assert_held_once(&uport->lock);
3008 uport->icount.cts++;
3010 if (uart_softcts_mode(uport)) {
3011 if (uport->hw_stopped) {
3013 uport->hw_stopped = 0;
3014 uport->ops->start_tx(uport);
3015 uart_write_wakeup(uport);
3019 uport->hw_stopped = 1;
3020 uport->ops->stop_tx(uport);
3026 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3029 * uart_insert_char - push a char to the uart layer
3031 * User is responsible to call tty_flip_buffer_push when they are done with
3034 * @port: corresponding port
3035 * @status: state of the serial port RX buffer (LSR for 8250)
3036 * @overrun: mask of overrun bits in @status
3037 * @ch: character to push
3038 * @flag: flag for the character (see TTY_NORMAL and friends)
3040 void uart_insert_char(struct uart_port *port, unsigned int status,
3041 unsigned int overrun, unsigned int ch, unsigned int flag)
3043 struct tty_port *tport = &port->state->port;
3045 if ((status & port->ignore_status_mask & ~overrun) == 0)
3046 if (tty_insert_flip_char(tport, ch, flag) == 0)
3047 ++port->icount.buf_overrun;
3050 * Overrun is special. Since it's reported immediately,
3051 * it doesn't affect the current character.
3053 if (status & ~port->ignore_status_mask & overrun)
3054 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3055 ++port->icount.buf_overrun;
3057 EXPORT_SYMBOL_GPL(uart_insert_char);
3059 EXPORT_SYMBOL(uart_write_wakeup);
3060 EXPORT_SYMBOL(uart_register_driver);
3061 EXPORT_SYMBOL(uart_unregister_driver);
3062 EXPORT_SYMBOL(uart_suspend_port);
3063 EXPORT_SYMBOL(uart_resume_port);
3064 EXPORT_SYMBOL(uart_add_one_port);
3065 EXPORT_SYMBOL(uart_remove_one_port);
3068 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3070 * @rs485conf: output parameter
3072 * This function implements the device tree binding described in
3073 * Documentation/devicetree/bindings/serial/rs485.txt.
3075 void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf)
3080 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3083 rs485conf->delay_rts_before_send = rs485_delay[0];
3084 rs485conf->delay_rts_after_send = rs485_delay[1];
3086 rs485conf->delay_rts_before_send = 0;
3087 rs485conf->delay_rts_after_send = 0;
3091 * Clear full-duplex and enabled flags, set RTS polarity to active high
3092 * to get to a defined state with the following properties:
3094 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3095 SER_RS485_RTS_AFTER_SEND);
3096 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3098 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3099 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3101 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3102 rs485conf->flags |= SER_RS485_ENABLED;
3104 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3105 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3106 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3109 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3111 MODULE_DESCRIPTION("Serial driver core");
3112 MODULE_LICENSE("GPL");