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 uart_port_lock_irqsave(__uport, &flags); \
86 #define uart_port_unlock(uport, flags) \
88 struct uart_port *__uport = uport; \
90 uart_port_unlock_irqrestore(__uport, 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 uart_state *state)
138 struct uart_port *port = state->uart_port;
139 struct serial_port_device *port_dev;
142 if (!port || port->flags & UPF_DEAD || uart_tx_stopped(port))
145 port_dev = port->port_dev;
147 /* Increment the runtime PM usage count for the active check below */
148 err = pm_runtime_get(&port_dev->dev);
149 if (err < 0 && err != -EINPROGRESS) {
150 pm_runtime_put_noidle(&port_dev->dev);
155 * Start TX if enabled, and kick runtime PM. If the device is not
156 * enabled, serial_port_runtime_resume() calls start_tx() again
157 * after enabling the device.
159 if (!pm_runtime_enabled(port->dev) || pm_runtime_active(&port_dev->dev))
160 port->ops->start_tx(port);
161 pm_runtime_mark_last_busy(&port_dev->dev);
162 pm_runtime_put_autosuspend(&port_dev->dev);
165 static void uart_start(struct tty_struct *tty)
167 struct uart_state *state = tty->driver_data;
168 struct uart_port *port;
171 port = uart_port_lock(state, flags);
173 uart_port_unlock(port, flags);
177 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
182 uart_port_lock_irqsave(port, &flags);
184 port->mctrl = (old & ~clear) | set;
185 if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))
186 port->ops->set_mctrl(port, port->mctrl);
187 uart_port_unlock_irqrestore(port, flags);
190 #define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
191 #define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
193 static void uart_port_dtr_rts(struct uart_port *uport, bool active)
196 uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
198 uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
201 /* Caller holds port mutex */
202 static void uart_change_line_settings(struct tty_struct *tty, struct uart_state *state,
203 const struct ktermios *old_termios)
205 struct uart_port *uport = uart_port_check(state);
206 struct ktermios *termios;
210 * If we have no tty, termios, or the port does not exist,
211 * then we can't set the parameters for this port.
213 if (!tty || uport->type == PORT_UNKNOWN)
216 termios = &tty->termios;
217 uport->ops->set_termios(uport, termios, old_termios);
220 * Set modem status enables based on termios cflag
222 uart_port_lock_irq(uport);
223 if (termios->c_cflag & CRTSCTS)
224 uport->status |= UPSTAT_CTS_ENABLE;
226 uport->status &= ~UPSTAT_CTS_ENABLE;
228 if (termios->c_cflag & CLOCAL)
229 uport->status &= ~UPSTAT_DCD_ENABLE;
231 uport->status |= UPSTAT_DCD_ENABLE;
233 /* reset sw-assisted CTS flow control based on (possibly) new mode */
234 old_hw_stopped = uport->hw_stopped;
235 uport->hw_stopped = uart_softcts_mode(uport) &&
236 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
237 if (uport->hw_stopped != old_hw_stopped) {
239 uport->ops->stop_tx(uport);
243 uart_port_unlock_irq(uport);
247 * Startup the port. This will be called once per open. All calls
248 * will be serialised by the per-port mutex.
250 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
253 struct uart_port *uport = uart_port_check(state);
258 if (uport->type == PORT_UNKNOWN)
262 * Make sure the device is in D0 state.
264 uart_change_pm(state, UART_PM_STATE_ON);
267 * Initialise and allocate the transmit and temporary
270 page = get_zeroed_page(GFP_KERNEL);
274 uart_port_lock(state, flags);
275 if (!state->xmit.buf) {
276 state->xmit.buf = (unsigned char *) page;
277 uart_circ_clear(&state->xmit);
278 uart_port_unlock(uport, flags);
280 uart_port_unlock(uport, flags);
282 * Do not free() the page under the port lock, see
288 retval = uport->ops->startup(uport);
290 if (uart_console(uport) && uport->cons->cflag) {
291 tty->termios.c_cflag = uport->cons->cflag;
292 tty->termios.c_ispeed = uport->cons->ispeed;
293 tty->termios.c_ospeed = uport->cons->ospeed;
294 uport->cons->cflag = 0;
295 uport->cons->ispeed = 0;
296 uport->cons->ospeed = 0;
299 * Initialise the hardware port settings.
301 uart_change_line_settings(tty, state, NULL);
304 * Setup the RTS and DTR signals once the
305 * port is open and ready to respond.
307 if (init_hw && C_BAUD(tty))
308 uart_port_dtr_rts(uport, true);
312 * This is to allow setserial on this port. People may want to set
313 * port/irq/type and then reconfigure the port properly if it failed
316 if (retval && capable(CAP_SYS_ADMIN))
322 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
325 struct tty_port *port = &state->port;
326 struct uart_port *uport;
329 if (tty_port_initialized(port))
330 goto out_base_port_startup;
332 retval = uart_port_startup(tty, state, init_hw);
334 set_bit(TTY_IO_ERROR, &tty->flags);
338 out_base_port_startup:
339 uport = uart_port_check(state);
343 serial_base_port_startup(uport);
349 * This routine will shutdown a serial port; interrupts are disabled, and
350 * DTR is dropped if the hangup on close termio flag is on. Calls to
351 * uart_shutdown are serialised by the per-port semaphore.
353 * uport == NULL if uart_port has already been removed
355 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
357 struct uart_port *uport = uart_port_check(state);
358 struct tty_port *port = &state->port;
360 char *xmit_buf = NULL;
363 * Set the TTY IO error marker
366 set_bit(TTY_IO_ERROR, &tty->flags);
369 serial_base_port_shutdown(uport);
371 if (tty_port_initialized(port)) {
372 tty_port_set_initialized(port, false);
375 * Turn off DTR and RTS early.
377 if (uport && uart_console(uport) && tty) {
378 uport->cons->cflag = tty->termios.c_cflag;
379 uport->cons->ispeed = tty->termios.c_ispeed;
380 uport->cons->ospeed = tty->termios.c_ospeed;
383 if (!tty || C_HUPCL(tty))
384 uart_port_dtr_rts(uport, false);
386 uart_port_shutdown(port);
390 * It's possible for shutdown to be called after suspend if we get
391 * a DCD drop (hangup) at just the right time. Clear suspended bit so
392 * we don't try to resume a port that has been shutdown.
394 tty_port_set_suspended(port, false);
397 * Do not free() the transmit buffer page under the port lock since
398 * this can create various circular locking scenarios. For instance,
399 * console driver may need to allocate/free a debug object, which
400 * can endup in printk() recursion.
402 uart_port_lock(state, flags);
403 xmit_buf = state->xmit.buf;
404 state->xmit.buf = NULL;
405 uart_port_unlock(uport, flags);
407 free_page((unsigned long)xmit_buf);
411 * uart_update_timeout - update per-port frame timing information
412 * @port: uart_port structure describing the port
413 * @cflag: termios cflag value
414 * @baud: speed of the port
416 * Set the @port frame timing information from which the FIFO timeout value is
417 * derived. The @cflag value should reflect the actual hardware settings as
418 * number of bits, parity, stop bits and baud rate is taken into account here.
420 * Locking: caller is expected to take @port->lock
423 uart_update_timeout(struct uart_port *port, unsigned int cflag,
426 u64 temp = tty_get_frame_size(cflag);
428 temp *= NSEC_PER_SEC;
429 port->frame_time = (unsigned int)DIV64_U64_ROUND_UP(temp, baud);
431 EXPORT_SYMBOL(uart_update_timeout);
434 * uart_get_baud_rate - return baud rate for a particular port
435 * @port: uart_port structure describing the port in question.
436 * @termios: desired termios settings
437 * @old: old termios (or %NULL)
438 * @min: minimum acceptable baud rate
439 * @max: maximum acceptable baud rate
441 * Decode the termios structure into a numeric baud rate, taking account of the
442 * magic 38400 baud rate (with spd_* flags), and mapping the %B0 rate to 9600
445 * If the new baud rate is invalid, try the @old termios setting. If it's still
446 * invalid, we try 9600 baud. If that is also invalid 0 is returned.
448 * The @termios structure is updated to reflect the baud rate we're actually
449 * going to be using. Don't do this for the case where B0 is requested ("hang
452 * Locking: caller dependent
455 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
456 const struct ktermios *old, unsigned int min, unsigned int max)
460 unsigned int altbaud;
462 upf_t flags = port->flags & UPF_SPD_MASK;
482 for (try = 0; try < 2; try++) {
483 baud = tty_termios_baud_rate(termios);
486 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
489 if (try == 0 && baud == 38400)
493 * Special case: B0 rate.
500 if (baud >= min && baud <= max)
504 * Oops, the quotient was zero. Try again with
505 * the old baud rate if possible.
507 termios->c_cflag &= ~CBAUD;
509 baud = tty_termios_baud_rate(old);
511 tty_termios_encode_baud_rate(termios,
518 * As a last resort, if the range cannot be met then clip to
519 * the nearest chip supported rate.
523 tty_termios_encode_baud_rate(termios,
526 tty_termios_encode_baud_rate(termios,
532 EXPORT_SYMBOL(uart_get_baud_rate);
535 * uart_get_divisor - return uart clock divisor
536 * @port: uart_port structure describing the port
537 * @baud: desired baud rate
539 * Calculate the divisor (baud_base / baud) for the specified @baud,
540 * appropriately rounded.
542 * If 38400 baud and custom divisor is selected, return the custom divisor
545 * Locking: caller dependent
548 uart_get_divisor(struct uart_port *port, unsigned int baud)
553 * Old custom speed handling.
555 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
556 quot = port->custom_divisor;
558 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
562 EXPORT_SYMBOL(uart_get_divisor);
564 static int uart_put_char(struct tty_struct *tty, u8 c)
566 struct uart_state *state = tty->driver_data;
567 struct uart_port *port;
568 struct circ_buf *circ;
573 port = uart_port_lock(state, flags);
575 uart_port_unlock(port, flags);
579 if (port && uart_circ_chars_free(circ) != 0) {
580 circ->buf[circ->head] = c;
581 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
584 uart_port_unlock(port, flags);
588 static void uart_flush_chars(struct tty_struct *tty)
593 static ssize_t uart_write(struct tty_struct *tty, const u8 *buf, size_t count)
595 struct uart_state *state = tty->driver_data;
596 struct uart_port *port;
597 struct circ_buf *circ;
602 * This means you called this function _after_ the port was
603 * closed. No cookie for you.
608 port = uart_port_lock(state, flags);
611 uart_port_unlock(port, flags);
616 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
621 memcpy(circ->buf + circ->head, buf, c);
622 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
629 uart_port_unlock(port, flags);
633 static unsigned int uart_write_room(struct tty_struct *tty)
635 struct uart_state *state = tty->driver_data;
636 struct uart_port *port;
640 port = uart_port_lock(state, flags);
641 ret = uart_circ_chars_free(&state->xmit);
642 uart_port_unlock(port, flags);
646 static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
648 struct uart_state *state = tty->driver_data;
649 struct uart_port *port;
653 port = uart_port_lock(state, flags);
654 ret = uart_circ_chars_pending(&state->xmit);
655 uart_port_unlock(port, flags);
659 static void uart_flush_buffer(struct tty_struct *tty)
661 struct uart_state *state = tty->driver_data;
662 struct uart_port *port;
666 * This means you called this function _after_ the port was
667 * closed. No cookie for you.
672 pr_debug("uart_flush_buffer(%d) called\n", tty->index);
674 port = uart_port_lock(state, flags);
677 uart_circ_clear(&state->xmit);
678 if (port->ops->flush_buffer)
679 port->ops->flush_buffer(port);
680 uart_port_unlock(port, flags);
681 tty_port_tty_wakeup(&state->port);
685 * This function performs low-level write of high-priority XON/XOFF
686 * character and accounting for it.
688 * Requires uart_port to implement .serial_out().
690 void uart_xchar_out(struct uart_port *uport, int offset)
692 serial_port_out(uport, offset, uport->x_char);
696 EXPORT_SYMBOL_GPL(uart_xchar_out);
699 * This function is used to send a high-priority XON/XOFF character to
702 static void uart_send_xchar(struct tty_struct *tty, u8 ch)
704 struct uart_state *state = tty->driver_data;
705 struct uart_port *port;
708 port = uart_port_ref(state);
712 if (port->ops->send_xchar)
713 port->ops->send_xchar(port, ch);
715 uart_port_lock_irqsave(port, &flags);
718 port->ops->start_tx(port);
719 uart_port_unlock_irqrestore(port, flags);
721 uart_port_deref(port);
724 static void uart_throttle(struct tty_struct *tty)
726 struct uart_state *state = tty->driver_data;
727 upstat_t mask = UPSTAT_SYNC_FIFO;
728 struct uart_port *port;
730 port = uart_port_ref(state);
735 mask |= UPSTAT_AUTOXOFF;
737 mask |= UPSTAT_AUTORTS;
739 if (port->status & mask) {
740 port->ops->throttle(port);
741 mask &= ~port->status;
744 if (mask & UPSTAT_AUTORTS)
745 uart_clear_mctrl(port, TIOCM_RTS);
747 if (mask & UPSTAT_AUTOXOFF)
748 uart_send_xchar(tty, STOP_CHAR(tty));
750 uart_port_deref(port);
753 static void uart_unthrottle(struct tty_struct *tty)
755 struct uart_state *state = tty->driver_data;
756 upstat_t mask = UPSTAT_SYNC_FIFO;
757 struct uart_port *port;
759 port = uart_port_ref(state);
764 mask |= UPSTAT_AUTOXOFF;
766 mask |= UPSTAT_AUTORTS;
768 if (port->status & mask) {
769 port->ops->unthrottle(port);
770 mask &= ~port->status;
773 if (mask & UPSTAT_AUTORTS)
774 uart_set_mctrl(port, TIOCM_RTS);
776 if (mask & UPSTAT_AUTOXOFF)
777 uart_send_xchar(tty, START_CHAR(tty));
779 uart_port_deref(port);
782 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
784 struct uart_state *state = container_of(port, struct uart_state, port);
785 struct uart_port *uport;
788 /* Initialize structure in case we error out later to prevent any stack info leakage. */
789 *retinfo = (struct serial_struct){};
792 * Ensure the state we copy is consistent and no hardware changes
795 mutex_lock(&port->mutex);
796 uport = uart_port_check(state);
800 retinfo->type = uport->type;
801 retinfo->line = uport->line;
802 retinfo->port = uport->iobase;
803 if (HIGH_BITS_OFFSET)
804 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
805 retinfo->irq = uport->irq;
806 retinfo->flags = (__force int)uport->flags;
807 retinfo->xmit_fifo_size = uport->fifosize;
808 retinfo->baud_base = uport->uartclk / 16;
809 retinfo->close_delay = jiffies_to_msecs(port->close_delay) / 10;
810 retinfo->closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
811 ASYNC_CLOSING_WAIT_NONE :
812 jiffies_to_msecs(port->closing_wait) / 10;
813 retinfo->custom_divisor = uport->custom_divisor;
814 retinfo->hub6 = uport->hub6;
815 retinfo->io_type = uport->iotype;
816 retinfo->iomem_reg_shift = uport->regshift;
817 retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
821 mutex_unlock(&port->mutex);
825 static int uart_get_info_user(struct tty_struct *tty,
826 struct serial_struct *ss)
828 struct uart_state *state = tty->driver_data;
829 struct tty_port *port = &state->port;
831 return uart_get_info(port, ss) < 0 ? -EIO : 0;
834 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
835 struct uart_state *state,
836 struct serial_struct *new_info)
838 struct uart_port *uport = uart_port_check(state);
839 unsigned long new_port;
840 unsigned int change_irq, change_port, closing_wait;
841 unsigned int old_custom_divisor, close_delay;
842 upf_t old_flags, new_flags;
848 new_port = new_info->port;
849 if (HIGH_BITS_OFFSET)
850 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
852 new_info->irq = irq_canonicalize(new_info->irq);
853 close_delay = msecs_to_jiffies(new_info->close_delay * 10);
854 closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
855 ASYNC_CLOSING_WAIT_NONE :
856 msecs_to_jiffies(new_info->closing_wait * 10);
859 change_irq = !(uport->flags & UPF_FIXED_PORT)
860 && new_info->irq != uport->irq;
863 * Since changing the 'type' of the port changes its resource
864 * allocations, we should treat type changes the same as
867 change_port = !(uport->flags & UPF_FIXED_PORT)
868 && (new_port != uport->iobase ||
869 (unsigned long)new_info->iomem_base != uport->mapbase ||
870 new_info->hub6 != uport->hub6 ||
871 new_info->io_type != uport->iotype ||
872 new_info->iomem_reg_shift != uport->regshift ||
873 new_info->type != uport->type);
875 old_flags = uport->flags;
876 new_flags = (__force upf_t)new_info->flags;
877 old_custom_divisor = uport->custom_divisor;
879 if (!capable(CAP_SYS_ADMIN)) {
881 if (change_irq || change_port ||
882 (new_info->baud_base != uport->uartclk / 16) ||
883 (close_delay != port->close_delay) ||
884 (closing_wait != port->closing_wait) ||
885 (new_info->xmit_fifo_size &&
886 new_info->xmit_fifo_size != uport->fifosize) ||
887 (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
889 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
890 (new_flags & UPF_USR_MASK));
891 uport->custom_divisor = new_info->custom_divisor;
895 if (change_irq || change_port) {
896 retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
902 * Ask the low level driver to verify the settings.
904 if (uport->ops->verify_port)
905 retval = uport->ops->verify_port(uport, new_info);
907 if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
908 (new_info->baud_base < 9600))
914 if (change_port || change_irq) {
918 * Make sure that we are the sole user of this port.
920 if (tty_port_users(port) > 1)
924 * We need to shutdown the serial port at the old
925 * port/type/irq combination.
927 uart_shutdown(tty, state);
931 unsigned long old_iobase, old_mapbase;
932 unsigned int old_type, old_iotype, old_hub6, old_shift;
934 old_iobase = uport->iobase;
935 old_mapbase = uport->mapbase;
936 old_type = uport->type;
937 old_hub6 = uport->hub6;
938 old_iotype = uport->iotype;
939 old_shift = uport->regshift;
942 * Free and release old regions
944 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
945 uport->ops->release_port(uport);
947 uport->iobase = new_port;
948 uport->type = new_info->type;
949 uport->hub6 = new_info->hub6;
950 uport->iotype = new_info->io_type;
951 uport->regshift = new_info->iomem_reg_shift;
952 uport->mapbase = (unsigned long)new_info->iomem_base;
955 * Claim and map the new regions
957 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
958 retval = uport->ops->request_port(uport);
960 /* Always success - Jean II */
965 * If we fail to request resources for the
966 * new port, try to restore the old settings.
969 uport->iobase = old_iobase;
970 uport->type = old_type;
971 uport->hub6 = old_hub6;
972 uport->iotype = old_iotype;
973 uport->regshift = old_shift;
974 uport->mapbase = old_mapbase;
976 if (old_type != PORT_UNKNOWN) {
977 retval = uport->ops->request_port(uport);
979 * If we failed to restore the old settings,
983 uport->type = PORT_UNKNOWN;
991 /* Added to return the correct error -Ram Gupta */
997 uport->irq = new_info->irq;
998 if (!(uport->flags & UPF_FIXED_PORT))
999 uport->uartclk = new_info->baud_base * 16;
1000 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
1001 (new_flags & UPF_CHANGE_MASK);
1002 uport->custom_divisor = new_info->custom_divisor;
1003 port->close_delay = close_delay;
1004 port->closing_wait = closing_wait;
1005 if (new_info->xmit_fifo_size)
1006 uport->fifosize = new_info->xmit_fifo_size;
1010 if (uport->type == PORT_UNKNOWN)
1012 if (tty_port_initialized(port)) {
1013 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
1014 old_custom_divisor != uport->custom_divisor) {
1016 * If they're setting up a custom divisor or speed,
1017 * instead of clearing it, then bitch about it.
1019 if (uport->flags & UPF_SPD_MASK) {
1020 dev_notice_ratelimited(uport->dev,
1021 "%s sets custom speed on %s. This is deprecated.\n",
1023 tty_name(port->tty));
1025 uart_change_line_settings(tty, state, NULL);
1028 retval = uart_startup(tty, state, true);
1030 tty_port_set_initialized(port, true);
1038 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1040 struct uart_state *state = tty->driver_data;
1041 struct tty_port *port = &state->port;
1044 down_write(&tty->termios_rwsem);
1046 * This semaphore protects port->count. It is also
1047 * very useful to prevent opens. Also, take the
1048 * port configuration semaphore to make sure that a
1049 * module insertion/removal doesn't change anything
1052 mutex_lock(&port->mutex);
1053 retval = uart_set_info(tty, port, state, ss);
1054 mutex_unlock(&port->mutex);
1055 up_write(&tty->termios_rwsem);
1060 * uart_get_lsr_info - get line status register info
1061 * @tty: tty associated with the UART
1062 * @state: UART being queried
1063 * @value: returned modem value
1065 static int uart_get_lsr_info(struct tty_struct *tty,
1066 struct uart_state *state, unsigned int __user *value)
1068 struct uart_port *uport = uart_port_check(state);
1069 unsigned int result;
1071 result = uport->ops->tx_empty(uport);
1074 * If we're about to load something into the transmit
1075 * register, we'll pretend the transmitter isn't empty to
1076 * avoid a race condition (depending on when the transmit
1077 * interrupt happens).
1079 if (uport->x_char ||
1080 ((uart_circ_chars_pending(&state->xmit) > 0) &&
1081 !uart_tx_stopped(uport)))
1082 result &= ~TIOCSER_TEMT;
1084 return put_user(result, value);
1087 static int uart_tiocmget(struct tty_struct *tty)
1089 struct uart_state *state = tty->driver_data;
1090 struct tty_port *port = &state->port;
1091 struct uart_port *uport;
1094 mutex_lock(&port->mutex);
1095 uport = uart_port_check(state);
1099 if (!tty_io_error(tty)) {
1100 uart_port_lock_irq(uport);
1101 result = uport->mctrl;
1102 result |= uport->ops->get_mctrl(uport);
1103 uart_port_unlock_irq(uport);
1106 mutex_unlock(&port->mutex);
1111 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1113 struct uart_state *state = tty->driver_data;
1114 struct tty_port *port = &state->port;
1115 struct uart_port *uport;
1118 mutex_lock(&port->mutex);
1119 uport = uart_port_check(state);
1123 if (!tty_io_error(tty)) {
1124 uart_update_mctrl(uport, set, clear);
1128 mutex_unlock(&port->mutex);
1132 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1134 struct uart_state *state = tty->driver_data;
1135 struct tty_port *port = &state->port;
1136 struct uart_port *uport;
1139 mutex_lock(&port->mutex);
1140 uport = uart_port_check(state);
1144 if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1145 uport->ops->break_ctl(uport, break_state);
1148 mutex_unlock(&port->mutex);
1152 static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1154 struct tty_port *port = &state->port;
1155 struct uart_port *uport;
1158 if (!capable(CAP_SYS_ADMIN))
1162 * Take the per-port semaphore. This prevents count from
1163 * changing, and hence any extra opens of the port while
1164 * we're auto-configuring.
1166 if (mutex_lock_interruptible(&port->mutex))
1167 return -ERESTARTSYS;
1169 uport = uart_port_check(state);
1176 if (tty_port_users(port) == 1) {
1177 uart_shutdown(tty, state);
1180 * If we already have a port type configured,
1181 * we must release its resources.
1183 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1184 uport->ops->release_port(uport);
1186 flags = UART_CONFIG_TYPE;
1187 if (uport->flags & UPF_AUTO_IRQ)
1188 flags |= UART_CONFIG_IRQ;
1191 * This will claim the ports resources if
1194 uport->ops->config_port(uport, flags);
1196 ret = uart_startup(tty, state, true);
1198 tty_port_set_initialized(port, true);
1203 mutex_unlock(&port->mutex);
1207 static void uart_enable_ms(struct uart_port *uport)
1210 * Force modem status interrupts on
1212 if (uport->ops->enable_ms)
1213 uport->ops->enable_ms(uport);
1217 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1218 * - mask passed in arg for lines of interest
1219 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1220 * Caller should use TIOCGICOUNT to see which one it was
1222 * FIXME: This wants extracting into a common all driver implementation
1223 * of TIOCMWAIT using tty_port.
1225 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1227 struct uart_port *uport;
1228 struct tty_port *port = &state->port;
1229 DECLARE_WAITQUEUE(wait, current);
1230 struct uart_icount cprev, cnow;
1234 * note the counters on entry
1236 uport = uart_port_ref(state);
1239 uart_port_lock_irq(uport);
1240 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1241 uart_enable_ms(uport);
1242 uart_port_unlock_irq(uport);
1244 add_wait_queue(&port->delta_msr_wait, &wait);
1246 uart_port_lock_irq(uport);
1247 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1248 uart_port_unlock_irq(uport);
1250 set_current_state(TASK_INTERRUPTIBLE);
1252 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1253 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1254 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1255 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1262 /* see if a signal did it */
1263 if (signal_pending(current)) {
1270 __set_current_state(TASK_RUNNING);
1271 remove_wait_queue(&port->delta_msr_wait, &wait);
1272 uart_port_deref(uport);
1278 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1279 * Return: write counters to the user passed counter struct
1280 * NB: both 1->0 and 0->1 transitions are counted except for
1281 * RI where only 0->1 is counted.
1283 static int uart_get_icount(struct tty_struct *tty,
1284 struct serial_icounter_struct *icount)
1286 struct uart_state *state = tty->driver_data;
1287 struct uart_icount cnow;
1288 struct uart_port *uport;
1290 uport = uart_port_ref(state);
1293 uart_port_lock_irq(uport);
1294 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1295 uart_port_unlock_irq(uport);
1296 uart_port_deref(uport);
1298 icount->cts = cnow.cts;
1299 icount->dsr = cnow.dsr;
1300 icount->rng = cnow.rng;
1301 icount->dcd = cnow.dcd;
1302 icount->rx = cnow.rx;
1303 icount->tx = cnow.tx;
1304 icount->frame = cnow.frame;
1305 icount->overrun = cnow.overrun;
1306 icount->parity = cnow.parity;
1307 icount->brk = cnow.brk;
1308 icount->buf_overrun = cnow.buf_overrun;
1313 #define SER_RS485_LEGACY_FLAGS (SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
1314 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
1315 SER_RS485_TERMINATE_BUS)
1317 static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
1319 u32 flags = rs485->flags;
1321 /* Don't return -EINVAL for unsupported legacy flags */
1322 flags &= ~SER_RS485_LEGACY_FLAGS;
1325 * For any bit outside of the legacy ones that is not supported by
1326 * the driver, return -EINVAL.
1328 if (flags & ~port->rs485_supported.flags)
1331 /* Asking for address w/o addressing mode? */
1332 if (!(rs485->flags & SER_RS485_ADDRB) &&
1333 (rs485->flags & (SER_RS485_ADDR_RECV|SER_RS485_ADDR_DEST)))
1336 /* Address given but not enabled? */
1337 if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv)
1339 if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest)
1345 static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
1346 struct serial_rs485 *rs485)
1348 if (!port->rs485_supported.delay_rts_before_send) {
1349 if (rs485->delay_rts_before_send) {
1350 dev_warn_ratelimited(port->dev,
1351 "%s (%d): RTS delay before sending not supported\n",
1352 port->name, port->line);
1354 rs485->delay_rts_before_send = 0;
1355 } else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) {
1356 rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY;
1357 dev_warn_ratelimited(port->dev,
1358 "%s (%d): RTS delay before sending clamped to %u ms\n",
1359 port->name, port->line, rs485->delay_rts_before_send);
1362 if (!port->rs485_supported.delay_rts_after_send) {
1363 if (rs485->delay_rts_after_send) {
1364 dev_warn_ratelimited(port->dev,
1365 "%s (%d): RTS delay after sending not supported\n",
1366 port->name, port->line);
1368 rs485->delay_rts_after_send = 0;
1369 } else if (rs485->delay_rts_after_send > RS485_MAX_RTS_DELAY) {
1370 rs485->delay_rts_after_send = RS485_MAX_RTS_DELAY;
1371 dev_warn_ratelimited(port->dev,
1372 "%s (%d): RTS delay after sending clamped to %u ms\n",
1373 port->name, port->line, rs485->delay_rts_after_send);
1377 static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485)
1379 u32 supported_flags = port->rs485_supported.flags;
1381 if (!(rs485->flags & SER_RS485_ENABLED)) {
1382 memset(rs485, 0, sizeof(*rs485));
1386 /* Clear other RS485 flags but SER_RS485_TERMINATE_BUS and return if enabling RS422 */
1387 if (rs485->flags & SER_RS485_MODE_RS422) {
1388 rs485->flags &= (SER_RS485_ENABLED | SER_RS485_MODE_RS422 | SER_RS485_TERMINATE_BUS);
1392 rs485->flags &= supported_flags;
1394 /* Pick sane settings if the user hasn't */
1395 if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
1396 !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
1397 if (supported_flags & SER_RS485_RTS_ON_SEND) {
1398 rs485->flags |= SER_RS485_RTS_ON_SEND;
1399 rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
1401 dev_warn_ratelimited(port->dev,
1402 "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
1403 port->name, port->line);
1405 rs485->flags |= SER_RS485_RTS_AFTER_SEND;
1406 rs485->flags &= ~SER_RS485_RTS_ON_SEND;
1408 dev_warn_ratelimited(port->dev,
1409 "%s (%d): invalid RTS setting, using RTS_AFTER_SEND instead\n",
1410 port->name, port->line);
1414 uart_sanitize_serial_rs485_delays(port, rs485);
1416 /* Return clean padding area to userspace */
1417 memset(rs485->padding0, 0, sizeof(rs485->padding0));
1418 memset(rs485->padding1, 0, sizeof(rs485->padding1));
1421 static void uart_set_rs485_termination(struct uart_port *port,
1422 const struct serial_rs485 *rs485)
1424 if (!(rs485->flags & SER_RS485_ENABLED))
1427 gpiod_set_value_cansleep(port->rs485_term_gpio,
1428 !!(rs485->flags & SER_RS485_TERMINATE_BUS));
1431 static void uart_set_rs485_rx_during_tx(struct uart_port *port,
1432 const struct serial_rs485 *rs485)
1434 if (!(rs485->flags & SER_RS485_ENABLED))
1437 gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1438 !!(rs485->flags & SER_RS485_RX_DURING_TX));
1441 static int uart_rs485_config(struct uart_port *port)
1443 struct serial_rs485 *rs485 = &port->rs485;
1444 unsigned long flags;
1447 if (!(rs485->flags & SER_RS485_ENABLED))
1450 uart_sanitize_serial_rs485(port, rs485);
1451 uart_set_rs485_termination(port, rs485);
1452 uart_set_rs485_rx_during_tx(port, rs485);
1454 uart_port_lock_irqsave(port, &flags);
1455 ret = port->rs485_config(port, NULL, rs485);
1456 uart_port_unlock_irqrestore(port, flags);
1458 memset(rs485, 0, sizeof(*rs485));
1460 gpiod_set_value_cansleep(port->rs485_term_gpio, 0);
1461 gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 0);
1467 static int uart_get_rs485_config(struct uart_port *port,
1468 struct serial_rs485 __user *rs485)
1470 unsigned long flags;
1471 struct serial_rs485 aux;
1473 uart_port_lock_irqsave(port, &flags);
1475 uart_port_unlock_irqrestore(port, flags);
1477 if (copy_to_user(rs485, &aux, sizeof(aux)))
1483 static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
1484 struct serial_rs485 __user *rs485_user)
1486 struct serial_rs485 rs485;
1488 unsigned long flags;
1490 if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
1493 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1496 ret = uart_check_rs485_flags(port, &rs485);
1499 uart_sanitize_serial_rs485(port, &rs485);
1500 uart_set_rs485_termination(port, &rs485);
1501 uart_set_rs485_rx_during_tx(port, &rs485);
1503 uart_port_lock_irqsave(port, &flags);
1504 ret = port->rs485_config(port, &tty->termios, &rs485);
1506 port->rs485 = rs485;
1508 /* Reset RTS and other mctrl lines when disabling RS485 */
1509 if (!(rs485.flags & SER_RS485_ENABLED))
1510 port->ops->set_mctrl(port, port->mctrl);
1512 uart_port_unlock_irqrestore(port, flags);
1514 /* restore old GPIO settings */
1515 gpiod_set_value_cansleep(port->rs485_term_gpio,
1516 !!(port->rs485.flags & SER_RS485_TERMINATE_BUS));
1517 gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1518 !!(port->rs485.flags & SER_RS485_RX_DURING_TX));
1522 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1528 static int uart_get_iso7816_config(struct uart_port *port,
1529 struct serial_iso7816 __user *iso7816)
1531 unsigned long flags;
1532 struct serial_iso7816 aux;
1534 if (!port->iso7816_config)
1537 uart_port_lock_irqsave(port, &flags);
1538 aux = port->iso7816;
1539 uart_port_unlock_irqrestore(port, flags);
1541 if (copy_to_user(iso7816, &aux, sizeof(aux)))
1547 static int uart_set_iso7816_config(struct uart_port *port,
1548 struct serial_iso7816 __user *iso7816_user)
1550 struct serial_iso7816 iso7816;
1552 unsigned long flags;
1554 if (!port->iso7816_config)
1557 if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1561 * There are 5 words reserved for future use. Check that userspace
1562 * doesn't put stuff in there to prevent breakages in the future.
1564 for (i = 0; i < ARRAY_SIZE(iso7816.reserved); i++)
1565 if (iso7816.reserved[i])
1568 uart_port_lock_irqsave(port, &flags);
1569 ret = port->iso7816_config(port, &iso7816);
1570 uart_port_unlock_irqrestore(port, flags);
1574 if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1581 * Called via sys_ioctl. We can use spin_lock_irq() here.
1584 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1586 struct uart_state *state = tty->driver_data;
1587 struct tty_port *port = &state->port;
1588 struct uart_port *uport;
1589 void __user *uarg = (void __user *)arg;
1590 int ret = -ENOIOCTLCMD;
1594 * These ioctls don't rely on the hardware to be present.
1598 down_write(&tty->termios_rwsem);
1599 ret = uart_do_autoconfig(tty, state);
1600 up_write(&tty->termios_rwsem);
1604 if (ret != -ENOIOCTLCMD)
1607 if (tty_io_error(tty)) {
1613 * The following should only be used when hardware is present.
1617 ret = uart_wait_modem_status(state, arg);
1621 if (ret != -ENOIOCTLCMD)
1624 /* rs485_config requires more locking than others */
1625 if (cmd == TIOCSRS485)
1626 down_write(&tty->termios_rwsem);
1628 mutex_lock(&port->mutex);
1629 uport = uart_port_check(state);
1631 if (!uport || tty_io_error(tty)) {
1637 * All these rely on hardware being present and need to be
1638 * protected against the tty being hung up.
1642 case TIOCSERGETLSR: /* Get line status register */
1643 ret = uart_get_lsr_info(tty, state, uarg);
1647 ret = uart_get_rs485_config(uport, uarg);
1651 ret = uart_set_rs485_config(tty, uport, uarg);
1655 ret = uart_set_iso7816_config(state->uart_port, uarg);
1659 ret = uart_get_iso7816_config(state->uart_port, uarg);
1662 if (uport->ops->ioctl)
1663 ret = uport->ops->ioctl(uport, cmd, arg);
1667 mutex_unlock(&port->mutex);
1668 if (cmd == TIOCSRS485)
1669 up_write(&tty->termios_rwsem);
1674 static void uart_set_ldisc(struct tty_struct *tty)
1676 struct uart_state *state = tty->driver_data;
1677 struct uart_port *uport;
1678 struct tty_port *port = &state->port;
1680 if (!tty_port_initialized(port))
1683 mutex_lock(&state->port.mutex);
1684 uport = uart_port_check(state);
1685 if (uport && uport->ops->set_ldisc)
1686 uport->ops->set_ldisc(uport, &tty->termios);
1687 mutex_unlock(&state->port.mutex);
1690 static void uart_set_termios(struct tty_struct *tty,
1691 const struct ktermios *old_termios)
1693 struct uart_state *state = tty->driver_data;
1694 struct uart_port *uport;
1695 unsigned int cflag = tty->termios.c_cflag;
1696 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1697 bool sw_changed = false;
1699 mutex_lock(&state->port.mutex);
1700 uport = uart_port_check(state);
1705 * Drivers doing software flow control also need to know
1706 * about changes to these input settings.
1708 if (uport->flags & UPF_SOFT_FLOW) {
1709 iflag_mask |= IXANY|IXON|IXOFF;
1711 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1712 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1716 * These are the bits that are used to setup various
1717 * flags in the low level driver. We can ignore the Bfoo
1718 * bits in c_cflag; c_[io]speed will always be set
1719 * appropriately by set_termios() in tty_ioctl.c
1721 if ((cflag ^ old_termios->c_cflag) == 0 &&
1722 tty->termios.c_ospeed == old_termios->c_ospeed &&
1723 tty->termios.c_ispeed == old_termios->c_ispeed &&
1724 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1729 uart_change_line_settings(tty, state, old_termios);
1730 /* reload cflag from termios; port driver may have overridden flags */
1731 cflag = tty->termios.c_cflag;
1733 /* Handle transition to B0 status */
1734 if (((old_termios->c_cflag & CBAUD) != B0) && ((cflag & CBAUD) == B0))
1735 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1736 /* Handle transition away from B0 status */
1737 else if (((old_termios->c_cflag & CBAUD) == B0) && ((cflag & CBAUD) != B0)) {
1738 unsigned int mask = TIOCM_DTR;
1740 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1742 uart_set_mctrl(uport, mask);
1745 mutex_unlock(&state->port.mutex);
1749 * Calls to uart_close() are serialised via the tty_lock in
1750 * drivers/tty/tty_io.c:tty_release()
1751 * drivers/tty/tty_io.c:do_tty_hangup()
1753 static void uart_close(struct tty_struct *tty, struct file *filp)
1755 struct uart_state *state = tty->driver_data;
1758 struct uart_driver *drv = tty->driver->driver_state;
1759 struct tty_port *port;
1761 state = drv->state + tty->index;
1762 port = &state->port;
1763 spin_lock_irq(&port->lock);
1765 spin_unlock_irq(&port->lock);
1769 pr_debug("uart_close(%d) called\n", tty->index);
1771 tty_port_close(tty->port, tty, filp);
1774 static void uart_tty_port_shutdown(struct tty_port *port)
1776 struct uart_state *state = container_of(port, struct uart_state, port);
1777 struct uart_port *uport = uart_port_check(state);
1781 * At this point, we stop accepting input. To do this, we
1782 * disable the receive line status interrupts.
1784 if (WARN(!uport, "detached port still initialized!\n"))
1787 uart_port_lock_irq(uport);
1788 uport->ops->stop_rx(uport);
1789 uart_port_unlock_irq(uport);
1791 serial_base_port_shutdown(uport);
1792 uart_port_shutdown(port);
1795 * It's possible for shutdown to be called after suspend if we get
1796 * a DCD drop (hangup) at just the right time. Clear suspended bit so
1797 * we don't try to resume a port that has been shutdown.
1799 tty_port_set_suspended(port, false);
1802 * Free the transmit buffer.
1804 uart_port_lock_irq(uport);
1805 uart_circ_clear(&state->xmit);
1806 buf = state->xmit.buf;
1807 state->xmit.buf = NULL;
1808 uart_port_unlock_irq(uport);
1810 free_page((unsigned long)buf);
1812 uart_change_pm(state, UART_PM_STATE_OFF);
1815 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1817 struct uart_state *state = tty->driver_data;
1818 struct uart_port *port;
1819 unsigned long char_time, expire, fifo_timeout;
1821 port = uart_port_ref(state);
1825 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1826 uart_port_deref(port);
1831 * Set the check interval to be 1/5 of the estimated time to
1832 * send a single character, and make it at least 1. The check
1833 * interval should also be less than the timeout.
1835 * Note: we have to use pretty tight timings here to satisfy
1838 char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
1840 if (timeout && timeout < char_time)
1841 char_time = timeout;
1843 if (!uart_cts_enabled(port)) {
1845 * If the transmitter hasn't cleared in twice the approximate
1846 * amount of time to send the entire FIFO, it probably won't
1847 * ever clear. This assumes the UART isn't doing flow
1848 * control, which is currently the case. Hence, if it ever
1849 * takes longer than FIFO timeout, this is probably due to a
1850 * UART bug of some kind. So, we clamp the timeout parameter at
1853 fifo_timeout = uart_fifo_timeout(port);
1854 if (timeout == 0 || timeout > 2 * fifo_timeout)
1855 timeout = 2 * fifo_timeout;
1858 expire = jiffies + timeout;
1860 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1861 port->line, jiffies, expire);
1864 * Check whether the transmitter is empty every 'char_time'.
1865 * 'timeout' / 'expire' give us the maximum amount of time
1868 while (!port->ops->tx_empty(port)) {
1869 msleep_interruptible(jiffies_to_msecs(char_time));
1870 if (signal_pending(current))
1872 if (timeout && time_after(jiffies, expire))
1875 uart_port_deref(port);
1879 * Calls to uart_hangup() are serialised by the tty_lock in
1880 * drivers/tty/tty_io.c:do_tty_hangup()
1881 * This runs from a workqueue and can sleep for a _short_ time only.
1883 static void uart_hangup(struct tty_struct *tty)
1885 struct uart_state *state = tty->driver_data;
1886 struct tty_port *port = &state->port;
1887 struct uart_port *uport;
1888 unsigned long flags;
1890 pr_debug("uart_hangup(%d)\n", tty->index);
1892 mutex_lock(&port->mutex);
1893 uport = uart_port_check(state);
1894 WARN(!uport, "hangup of detached port!\n");
1896 if (tty_port_active(port)) {
1897 uart_flush_buffer(tty);
1898 uart_shutdown(tty, state);
1899 spin_lock_irqsave(&port->lock, flags);
1901 spin_unlock_irqrestore(&port->lock, flags);
1902 tty_port_set_active(port, false);
1903 tty_port_tty_set(port, NULL);
1904 if (uport && !uart_console(uport))
1905 uart_change_pm(state, UART_PM_STATE_OFF);
1906 wake_up_interruptible(&port->open_wait);
1907 wake_up_interruptible(&port->delta_msr_wait);
1909 mutex_unlock(&port->mutex);
1912 /* uport == NULL if uart_port has already been removed */
1913 static void uart_port_shutdown(struct tty_port *port)
1915 struct uart_state *state = container_of(port, struct uart_state, port);
1916 struct uart_port *uport = uart_port_check(state);
1919 * clear delta_msr_wait queue to avoid mem leaks: we may free
1920 * the irq here so the queue might never be woken up. Note
1921 * that we won't end up waiting on delta_msr_wait again since
1922 * any outstanding file descriptors should be pointing at
1923 * hung_up_tty_fops now.
1925 wake_up_interruptible(&port->delta_msr_wait);
1928 /* Free the IRQ and disable the port. */
1929 uport->ops->shutdown(uport);
1931 /* Ensure that the IRQ handler isn't running on another CPU. */
1932 synchronize_irq(uport->irq);
1936 static bool uart_carrier_raised(struct tty_port *port)
1938 struct uart_state *state = container_of(port, struct uart_state, port);
1939 struct uart_port *uport;
1942 uport = uart_port_ref(state);
1944 * Should never observe uport == NULL since checks for hangup should
1945 * abort the tty_port_block_til_ready() loop before checking for carrier
1946 * raised -- but report carrier raised if it does anyway so open will
1947 * continue and not sleep
1949 if (WARN_ON(!uport))
1951 uart_port_lock_irq(uport);
1952 uart_enable_ms(uport);
1953 mctrl = uport->ops->get_mctrl(uport);
1954 uart_port_unlock_irq(uport);
1955 uart_port_deref(uport);
1957 return mctrl & TIOCM_CAR;
1960 static void uart_dtr_rts(struct tty_port *port, bool active)
1962 struct uart_state *state = container_of(port, struct uart_state, port);
1963 struct uart_port *uport;
1965 uport = uart_port_ref(state);
1968 uart_port_dtr_rts(uport, active);
1969 uart_port_deref(uport);
1972 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1974 struct uart_driver *drv = driver->driver_state;
1975 struct uart_state *state = drv->state + tty->index;
1977 tty->driver_data = state;
1979 return tty_standard_install(driver, tty);
1983 * Calls to uart_open are serialised by the tty_lock in
1984 * drivers/tty/tty_io.c:tty_open()
1985 * Note that if this fails, then uart_close() _will_ be called.
1987 * In time, we want to scrap the "opening nonpresent ports"
1988 * behaviour and implement an alternative way for setserial
1989 * to set base addresses/ports/types. This will allow us to
1990 * get rid of a certain amount of extra tests.
1992 static int uart_open(struct tty_struct *tty, struct file *filp)
1994 struct uart_state *state = tty->driver_data;
1997 retval = tty_port_open(&state->port, tty, filp);
2004 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
2006 struct uart_state *state = container_of(port, struct uart_state, port);
2007 struct uart_port *uport;
2010 uport = uart_port_check(state);
2011 if (!uport || uport->flags & UPF_DEAD)
2015 * Start up the serial port.
2017 ret = uart_startup(tty, state, false);
2019 tty_port_set_active(port, true);
2024 static const char *uart_type(struct uart_port *port)
2026 const char *str = NULL;
2028 if (port->ops->type)
2029 str = port->ops->type(port);
2037 #ifdef CONFIG_PROC_FS
2039 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
2041 struct uart_state *state = drv->state + i;
2042 struct tty_port *port = &state->port;
2043 enum uart_pm_state pm_state;
2044 struct uart_port *uport;
2046 unsigned int status;
2049 mutex_lock(&port->mutex);
2050 uport = uart_port_check(state);
2054 mmio = uport->iotype >= UPIO_MEM;
2055 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
2056 uport->line, uart_type(uport),
2057 mmio ? "mmio:0x" : "port:",
2058 mmio ? (unsigned long long)uport->mapbase
2059 : (unsigned long long)uport->iobase,
2062 if (uport->type == PORT_UNKNOWN) {
2067 if (capable(CAP_SYS_ADMIN)) {
2068 pm_state = state->pm_state;
2069 if (pm_state != UART_PM_STATE_ON)
2070 uart_change_pm(state, UART_PM_STATE_ON);
2071 uart_port_lock_irq(uport);
2072 status = uport->ops->get_mctrl(uport);
2073 uart_port_unlock_irq(uport);
2074 if (pm_state != UART_PM_STATE_ON)
2075 uart_change_pm(state, pm_state);
2077 seq_printf(m, " tx:%d rx:%d",
2078 uport->icount.tx, uport->icount.rx);
2079 if (uport->icount.frame)
2080 seq_printf(m, " fe:%d", uport->icount.frame);
2081 if (uport->icount.parity)
2082 seq_printf(m, " pe:%d", uport->icount.parity);
2083 if (uport->icount.brk)
2084 seq_printf(m, " brk:%d", uport->icount.brk);
2085 if (uport->icount.overrun)
2086 seq_printf(m, " oe:%d", uport->icount.overrun);
2087 if (uport->icount.buf_overrun)
2088 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
2090 #define INFOBIT(bit, str) \
2091 if (uport->mctrl & (bit)) \
2092 strncat(stat_buf, (str), sizeof(stat_buf) - \
2093 strlen(stat_buf) - 2)
2094 #define STATBIT(bit, str) \
2095 if (status & (bit)) \
2096 strncat(stat_buf, (str), sizeof(stat_buf) - \
2097 strlen(stat_buf) - 2)
2101 INFOBIT(TIOCM_RTS, "|RTS");
2102 STATBIT(TIOCM_CTS, "|CTS");
2103 INFOBIT(TIOCM_DTR, "|DTR");
2104 STATBIT(TIOCM_DSR, "|DSR");
2105 STATBIT(TIOCM_CAR, "|CD");
2106 STATBIT(TIOCM_RNG, "|RI");
2110 seq_puts(m, stat_buf);
2116 mutex_unlock(&port->mutex);
2119 static int uart_proc_show(struct seq_file *m, void *v)
2121 struct tty_driver *ttydrv = m->private;
2122 struct uart_driver *drv = ttydrv->driver_state;
2125 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
2126 for (i = 0; i < drv->nr; i++)
2127 uart_line_info(m, drv, i);
2132 static void uart_port_spin_lock_init(struct uart_port *port)
2134 spin_lock_init(&port->lock);
2135 lockdep_set_class(&port->lock, &port_lock_key);
2138 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
2140 * uart_console_write - write a console message to a serial port
2141 * @port: the port to write the message
2142 * @s: array of characters
2143 * @count: number of characters in string to write
2144 * @putchar: function to write character to port
2146 void uart_console_write(struct uart_port *port, const char *s,
2148 void (*putchar)(struct uart_port *, unsigned char))
2152 for (i = 0; i < count; i++, s++) {
2154 putchar(port, '\r');
2158 EXPORT_SYMBOL_GPL(uart_console_write);
2161 * uart_get_console - get uart port for console
2162 * @ports: ports to search in
2163 * @nr: number of @ports
2164 * @co: console to search for
2165 * Returns: uart_port for the console @co
2167 * Check whether an invalid uart number has been specified (as @co->index), and
2168 * if so, search for the first available port that does have console support.
2170 struct uart_port * __init
2171 uart_get_console(struct uart_port *ports, int nr, struct console *co)
2173 int idx = co->index;
2175 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
2176 ports[idx].membase == NULL))
2177 for (idx = 0; idx < nr; idx++)
2178 if (ports[idx].iobase != 0 ||
2179 ports[idx].membase != NULL)
2188 * uart_parse_earlycon - Parse earlycon options
2189 * @p: ptr to 2nd field (ie., just beyond '<name>,')
2190 * @iotype: ptr for decoded iotype (out)
2191 * @addr: ptr for decoded mapbase/iobase (out)
2192 * @options: ptr for <options> field; %NULL if not present (out)
2194 * Decodes earlycon kernel command line parameters of the form:
2195 * * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2196 * * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2198 * The optional form:
2199 * * earlycon=<name>,0x<addr>,<options>
2200 * * console=<name>,0x<addr>,<options>
2202 * is also accepted; the returned @iotype will be %UPIO_MEM.
2204 * Returns: 0 on success or -%EINVAL on failure
2206 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
2209 if (strncmp(p, "mmio,", 5) == 0) {
2212 } else if (strncmp(p, "mmio16,", 7) == 0) {
2213 *iotype = UPIO_MEM16;
2215 } else if (strncmp(p, "mmio32,", 7) == 0) {
2216 *iotype = UPIO_MEM32;
2218 } else if (strncmp(p, "mmio32be,", 9) == 0) {
2219 *iotype = UPIO_MEM32BE;
2221 } else if (strncmp(p, "mmio32native,", 13) == 0) {
2222 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2223 UPIO_MEM32BE : UPIO_MEM32;
2225 } else if (strncmp(p, "io,", 3) == 0) {
2226 *iotype = UPIO_PORT;
2228 } else if (strncmp(p, "0x", 2) == 0) {
2235 * Before you replace it with kstrtoull(), think about options separator
2236 * (',') it will not tolerate
2238 *addr = simple_strtoull(p, NULL, 0);
2246 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2249 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2250 * @options: pointer to option string
2251 * @baud: pointer to an 'int' variable for the baud rate.
2252 * @parity: pointer to an 'int' variable for the parity.
2253 * @bits: pointer to an 'int' variable for the number of data bits.
2254 * @flow: pointer to an 'int' variable for the flow control character.
2256 * uart_parse_options() decodes a string containing the serial console
2257 * options. The format of the string is <baud><parity><bits><flow>,
2261 uart_parse_options(const char *options, int *baud, int *parity,
2262 int *bits, int *flow)
2264 const char *s = options;
2266 *baud = simple_strtoul(s, NULL, 10);
2267 while (*s >= '0' && *s <= '9')
2276 EXPORT_SYMBOL_GPL(uart_parse_options);
2279 * uart_set_options - setup the serial console parameters
2280 * @port: pointer to the serial ports uart_port structure
2281 * @co: console pointer
2283 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2284 * @bits: number of data bits
2285 * @flow: flow control character - 'r' (rts)
2287 * Locking: Caller must hold console_list_lock in order to serialize
2288 * early initialization of the serial-console lock.
2291 uart_set_options(struct uart_port *port, struct console *co,
2292 int baud, int parity, int bits, int flow)
2294 struct ktermios termios;
2295 static struct ktermios dummy;
2298 * Ensure that the serial-console lock is initialised early.
2300 * Note that the console-registered check is needed because
2301 * kgdboc can call uart_set_options() for an already registered
2302 * console via tty_find_polling_driver() and uart_poll_init().
2304 if (!uart_console_registered_locked(port) && !port->console_reinit)
2305 uart_port_spin_lock_init(port);
2307 memset(&termios, 0, sizeof(struct ktermios));
2309 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2310 tty_termios_encode_baud_rate(&termios, baud, baud);
2313 termios.c_cflag |= CS7;
2315 termios.c_cflag |= CS8;
2319 termios.c_cflag |= PARODD;
2322 termios.c_cflag |= PARENB;
2327 termios.c_cflag |= CRTSCTS;
2330 * some uarts on other side don't support no flow control.
2331 * So we set * DTR in host uart to make them happy
2333 port->mctrl |= TIOCM_DTR;
2335 port->ops->set_termios(port, &termios, &dummy);
2337 * Allow the setting of the UART parameters with a NULL console
2341 co->cflag = termios.c_cflag;
2342 co->ispeed = termios.c_ispeed;
2343 co->ospeed = termios.c_ospeed;
2348 EXPORT_SYMBOL_GPL(uart_set_options);
2349 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2352 * uart_change_pm - set power state of the port
2354 * @state: port descriptor
2355 * @pm_state: new state
2357 * Locking: port->mutex has to be held
2359 static void uart_change_pm(struct uart_state *state,
2360 enum uart_pm_state pm_state)
2362 struct uart_port *port = uart_port_check(state);
2364 if (state->pm_state != pm_state) {
2365 if (port && port->ops->pm)
2366 port->ops->pm(port, pm_state, state->pm_state);
2367 state->pm_state = pm_state;
2372 struct uart_port *port;
2373 struct uart_driver *driver;
2376 static int serial_match_port(struct device *dev, void *data)
2378 struct uart_match *match = data;
2379 struct tty_driver *tty_drv = match->driver->tty_driver;
2380 dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2383 return dev->devt == devt; /* Actually, only one tty per port */
2386 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2388 struct uart_state *state = drv->state + uport->line;
2389 struct tty_port *port = &state->port;
2390 struct device *tty_dev;
2391 struct uart_match match = {uport, drv};
2393 mutex_lock(&port->mutex);
2395 tty_dev = device_find_child(&uport->port_dev->dev, &match, serial_match_port);
2396 if (tty_dev && device_may_wakeup(tty_dev)) {
2397 enable_irq_wake(uport->irq);
2398 put_device(tty_dev);
2399 mutex_unlock(&port->mutex);
2402 put_device(tty_dev);
2405 * Nothing to do if the console is not suspending
2406 * except stop_rx to prevent any asynchronous data
2407 * over RX line. However ensure that we will be
2408 * able to Re-start_rx later.
2410 if (!console_suspend_enabled && uart_console(uport)) {
2411 if (uport->ops->start_rx) {
2412 uart_port_lock_irq(uport);
2413 uport->ops->stop_rx(uport);
2414 uart_port_unlock_irq(uport);
2419 uport->suspended = 1;
2421 if (tty_port_initialized(port)) {
2422 const struct uart_ops *ops = uport->ops;
2426 tty_port_set_suspended(port, true);
2427 tty_port_set_initialized(port, false);
2429 uart_port_lock_irq(uport);
2430 ops->stop_tx(uport);
2431 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2432 ops->set_mctrl(uport, 0);
2433 /* save mctrl so it can be restored on resume */
2434 mctrl = uport->mctrl;
2436 ops->stop_rx(uport);
2437 uart_port_unlock_irq(uport);
2440 * Wait for the transmitter to empty.
2442 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2445 dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2448 ops->shutdown(uport);
2449 uport->mctrl = mctrl;
2453 * Disable the console device before suspending.
2455 if (uart_console(uport))
2456 console_stop(uport->cons);
2458 uart_change_pm(state, UART_PM_STATE_OFF);
2460 mutex_unlock(&port->mutex);
2464 EXPORT_SYMBOL(uart_suspend_port);
2466 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2468 struct uart_state *state = drv->state + uport->line;
2469 struct tty_port *port = &state->port;
2470 struct device *tty_dev;
2471 struct uart_match match = {uport, drv};
2472 struct ktermios termios;
2474 mutex_lock(&port->mutex);
2476 tty_dev = device_find_child(&uport->port_dev->dev, &match, serial_match_port);
2477 if (!uport->suspended && device_may_wakeup(tty_dev)) {
2478 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2479 disable_irq_wake(uport->irq);
2480 put_device(tty_dev);
2481 mutex_unlock(&port->mutex);
2484 put_device(tty_dev);
2485 uport->suspended = 0;
2488 * Re-enable the console device after suspending.
2490 if (uart_console(uport)) {
2492 * First try to use the console cflag setting.
2494 memset(&termios, 0, sizeof(struct ktermios));
2495 termios.c_cflag = uport->cons->cflag;
2496 termios.c_ispeed = uport->cons->ispeed;
2497 termios.c_ospeed = uport->cons->ospeed;
2500 * If that's unset, use the tty termios setting.
2502 if (port->tty && termios.c_cflag == 0)
2503 termios = port->tty->termios;
2505 if (console_suspend_enabled)
2506 uart_change_pm(state, UART_PM_STATE_ON);
2507 uport->ops->set_termios(uport, &termios, NULL);
2508 if (!console_suspend_enabled && uport->ops->start_rx) {
2509 uart_port_lock_irq(uport);
2510 uport->ops->start_rx(uport);
2511 uart_port_unlock_irq(uport);
2513 if (console_suspend_enabled)
2514 console_start(uport->cons);
2517 if (tty_port_suspended(port)) {
2518 const struct uart_ops *ops = uport->ops;
2521 uart_change_pm(state, UART_PM_STATE_ON);
2522 uart_port_lock_irq(uport);
2523 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2524 ops->set_mctrl(uport, 0);
2525 uart_port_unlock_irq(uport);
2526 if (console_suspend_enabled || !uart_console(uport)) {
2527 /* Protected by port mutex for now */
2528 struct tty_struct *tty = port->tty;
2530 ret = ops->startup(uport);
2533 uart_change_line_settings(tty, state, NULL);
2534 uart_rs485_config(uport);
2535 uart_port_lock_irq(uport);
2536 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2537 ops->set_mctrl(uport, uport->mctrl);
2538 ops->start_tx(uport);
2539 uart_port_unlock_irq(uport);
2540 tty_port_set_initialized(port, true);
2543 * Failed to resume - maybe hardware went away?
2544 * Clear the "initialized" flag so we won't try
2545 * to call the low level drivers shutdown method.
2547 uart_shutdown(tty, state);
2551 tty_port_set_suspended(port, false);
2554 mutex_unlock(&port->mutex);
2558 EXPORT_SYMBOL(uart_resume_port);
2561 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2565 switch (port->iotype) {
2567 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2570 snprintf(address, sizeof(address),
2571 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2579 snprintf(address, sizeof(address),
2580 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2583 strscpy(address, "*unknown*", sizeof(address));
2587 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2588 port->dev ? dev_name(port->dev) : "",
2589 port->dev ? ": " : "",
2591 address, port->irq, port->uartclk / 16, uart_type(port));
2593 /* The magic multiplier feature is a bit obscure, so report it too. */
2594 if (port->flags & UPF_MAGIC_MULTIPLIER)
2595 pr_info("%s%s%s extra baud rates supported: %d, %d",
2596 port->dev ? dev_name(port->dev) : "",
2597 port->dev ? ": " : "",
2599 port->uartclk / 8, port->uartclk / 4);
2603 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2604 struct uart_port *port)
2609 * If there isn't a port here, don't do anything further.
2611 if (!port->iobase && !port->mapbase && !port->membase)
2615 * Now do the auto configuration stuff. Note that config_port
2616 * is expected to claim the resources and map the port for us.
2619 if (port->flags & UPF_AUTO_IRQ)
2620 flags |= UART_CONFIG_IRQ;
2621 if (port->flags & UPF_BOOT_AUTOCONF) {
2622 if (!(port->flags & UPF_FIXED_TYPE)) {
2623 port->type = PORT_UNKNOWN;
2624 flags |= UART_CONFIG_TYPE;
2626 /* Synchronize with possible boot console. */
2627 if (uart_console(port))
2629 port->ops->config_port(port, flags);
2630 if (uart_console(port))
2634 if (port->type != PORT_UNKNOWN) {
2635 unsigned long flags;
2637 uart_report_port(drv, port);
2639 /* Synchronize with possible boot console. */
2640 if (uart_console(port))
2643 /* Power up port for set_mctrl() */
2644 uart_change_pm(state, UART_PM_STATE_ON);
2647 * Ensure that the modem control lines are de-activated.
2648 * keep the DTR setting that is set in uart_set_options()
2649 * We probably don't need a spinlock around this, but
2651 uart_port_lock_irqsave(port, &flags);
2652 port->mctrl &= TIOCM_DTR;
2653 if (!(port->rs485.flags & SER_RS485_ENABLED))
2654 port->ops->set_mctrl(port, port->mctrl);
2655 uart_port_unlock_irqrestore(port, flags);
2657 uart_rs485_config(port);
2659 if (uart_console(port))
2663 * If this driver supports console, and it hasn't been
2664 * successfully registered yet, try to re-register it.
2665 * It may be that the port was not available.
2667 if (port->cons && !console_is_registered(port->cons))
2668 register_console(port->cons);
2671 * Power down all ports by default, except the
2672 * console if we have one.
2674 if (!uart_console(port))
2675 uart_change_pm(state, UART_PM_STATE_OFF);
2679 #ifdef CONFIG_CONSOLE_POLL
2681 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2683 struct uart_driver *drv = driver->driver_state;
2684 struct uart_state *state = drv->state + line;
2685 enum uart_pm_state pm_state;
2686 struct tty_port *tport;
2687 struct uart_port *port;
2694 tport = &state->port;
2695 mutex_lock(&tport->mutex);
2697 port = uart_port_check(state);
2698 if (!port || port->type == PORT_UNKNOWN ||
2699 !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2704 pm_state = state->pm_state;
2705 uart_change_pm(state, UART_PM_STATE_ON);
2707 if (port->ops->poll_init) {
2709 * We don't set initialized as we only initialized the hw,
2710 * e.g. state->xmit is still uninitialized.
2712 if (!tty_port_initialized(tport))
2713 ret = port->ops->poll_init(port);
2716 if (!ret && options) {
2717 uart_parse_options(options, &baud, &parity, &bits, &flow);
2718 console_list_lock();
2719 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2720 console_list_unlock();
2724 uart_change_pm(state, pm_state);
2725 mutex_unlock(&tport->mutex);
2729 static int uart_poll_get_char(struct tty_driver *driver, int line)
2731 struct uart_driver *drv = driver->driver_state;
2732 struct uart_state *state = drv->state + line;
2733 struct uart_port *port;
2736 port = uart_port_ref(state);
2738 ret = port->ops->poll_get_char(port);
2739 uart_port_deref(port);
2745 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2747 struct uart_driver *drv = driver->driver_state;
2748 struct uart_state *state = drv->state + line;
2749 struct uart_port *port;
2751 port = uart_port_ref(state);
2756 port->ops->poll_put_char(port, '\r');
2757 port->ops->poll_put_char(port, ch);
2758 uart_port_deref(port);
2762 static const struct tty_operations uart_ops = {
2763 .install = uart_install,
2765 .close = uart_close,
2766 .write = uart_write,
2767 .put_char = uart_put_char,
2768 .flush_chars = uart_flush_chars,
2769 .write_room = uart_write_room,
2770 .chars_in_buffer= uart_chars_in_buffer,
2771 .flush_buffer = uart_flush_buffer,
2772 .ioctl = uart_ioctl,
2773 .throttle = uart_throttle,
2774 .unthrottle = uart_unthrottle,
2775 .send_xchar = uart_send_xchar,
2776 .set_termios = uart_set_termios,
2777 .set_ldisc = uart_set_ldisc,
2779 .start = uart_start,
2780 .hangup = uart_hangup,
2781 .break_ctl = uart_break_ctl,
2782 .wait_until_sent= uart_wait_until_sent,
2783 #ifdef CONFIG_PROC_FS
2784 .proc_show = uart_proc_show,
2786 .tiocmget = uart_tiocmget,
2787 .tiocmset = uart_tiocmset,
2788 .set_serial = uart_set_info_user,
2789 .get_serial = uart_get_info_user,
2790 .get_icount = uart_get_icount,
2791 #ifdef CONFIG_CONSOLE_POLL
2792 .poll_init = uart_poll_init,
2793 .poll_get_char = uart_poll_get_char,
2794 .poll_put_char = uart_poll_put_char,
2798 static const struct tty_port_operations uart_port_ops = {
2799 .carrier_raised = uart_carrier_raised,
2800 .dtr_rts = uart_dtr_rts,
2801 .activate = uart_port_activate,
2802 .shutdown = uart_tty_port_shutdown,
2806 * uart_register_driver - register a driver with the uart core layer
2807 * @drv: low level driver structure
2809 * Register a uart driver with the core driver. We in turn register with the
2810 * tty layer, and initialise the core driver per-port state.
2812 * We have a proc file in /proc/tty/driver which is named after the normal
2815 * @drv->port should be %NULL, and the per-port structures should be registered
2816 * using uart_add_one_port() after this call has succeeded.
2818 * Locking: none, Interrupts: enabled
2820 int uart_register_driver(struct uart_driver *drv)
2822 struct tty_driver *normal;
2823 int i, retval = -ENOMEM;
2828 * Maybe we should be using a slab cache for this, especially if
2829 * we have a large number of ports to handle.
2831 drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2835 normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
2836 TTY_DRIVER_DYNAMIC_DEV);
2837 if (IS_ERR(normal)) {
2838 retval = PTR_ERR(normal);
2842 drv->tty_driver = normal;
2844 normal->driver_name = drv->driver_name;
2845 normal->name = drv->dev_name;
2846 normal->major = drv->major;
2847 normal->minor_start = drv->minor;
2848 normal->type = TTY_DRIVER_TYPE_SERIAL;
2849 normal->subtype = SERIAL_TYPE_NORMAL;
2850 normal->init_termios = tty_std_termios;
2851 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2852 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2853 normal->driver_state = drv;
2854 tty_set_operations(normal, &uart_ops);
2857 * Initialise the UART state(s).
2859 for (i = 0; i < drv->nr; i++) {
2860 struct uart_state *state = drv->state + i;
2861 struct tty_port *port = &state->port;
2863 tty_port_init(port);
2864 port->ops = &uart_port_ops;
2867 retval = tty_register_driver(normal);
2871 for (i = 0; i < drv->nr; i++)
2872 tty_port_destroy(&drv->state[i].port);
2873 tty_driver_kref_put(normal);
2879 EXPORT_SYMBOL(uart_register_driver);
2882 * uart_unregister_driver - remove a driver from the uart core layer
2883 * @drv: low level driver structure
2885 * Remove all references to a driver from the core driver. The low level
2886 * driver must have removed all its ports via the uart_remove_one_port() if it
2887 * registered them with uart_add_one_port(). (I.e. @drv->port is %NULL.)
2889 * Locking: none, Interrupts: enabled
2891 void uart_unregister_driver(struct uart_driver *drv)
2893 struct tty_driver *p = drv->tty_driver;
2896 tty_unregister_driver(p);
2897 tty_driver_kref_put(p);
2898 for (i = 0; i < drv->nr; i++)
2899 tty_port_destroy(&drv->state[i].port);
2902 drv->tty_driver = NULL;
2904 EXPORT_SYMBOL(uart_unregister_driver);
2906 struct tty_driver *uart_console_device(struct console *co, int *index)
2908 struct uart_driver *p = co->data;
2910 return p->tty_driver;
2912 EXPORT_SYMBOL_GPL(uart_console_device);
2914 static ssize_t uartclk_show(struct device *dev,
2915 struct device_attribute *attr, char *buf)
2917 struct serial_struct tmp;
2918 struct tty_port *port = dev_get_drvdata(dev);
2920 uart_get_info(port, &tmp);
2921 return sprintf(buf, "%d\n", tmp.baud_base * 16);
2924 static ssize_t type_show(struct device *dev,
2925 struct device_attribute *attr, char *buf)
2927 struct serial_struct tmp;
2928 struct tty_port *port = dev_get_drvdata(dev);
2930 uart_get_info(port, &tmp);
2931 return sprintf(buf, "%d\n", tmp.type);
2934 static ssize_t line_show(struct device *dev,
2935 struct device_attribute *attr, char *buf)
2937 struct serial_struct tmp;
2938 struct tty_port *port = dev_get_drvdata(dev);
2940 uart_get_info(port, &tmp);
2941 return sprintf(buf, "%d\n", tmp.line);
2944 static ssize_t port_show(struct device *dev,
2945 struct device_attribute *attr, char *buf)
2947 struct serial_struct tmp;
2948 struct tty_port *port = dev_get_drvdata(dev);
2949 unsigned long ioaddr;
2951 uart_get_info(port, &tmp);
2953 if (HIGH_BITS_OFFSET)
2954 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2955 return sprintf(buf, "0x%lX\n", ioaddr);
2958 static ssize_t irq_show(struct device *dev,
2959 struct device_attribute *attr, char *buf)
2961 struct serial_struct tmp;
2962 struct tty_port *port = dev_get_drvdata(dev);
2964 uart_get_info(port, &tmp);
2965 return sprintf(buf, "%d\n", tmp.irq);
2968 static ssize_t flags_show(struct device *dev,
2969 struct device_attribute *attr, char *buf)
2971 struct serial_struct tmp;
2972 struct tty_port *port = dev_get_drvdata(dev);
2974 uart_get_info(port, &tmp);
2975 return sprintf(buf, "0x%X\n", tmp.flags);
2978 static ssize_t xmit_fifo_size_show(struct device *dev,
2979 struct device_attribute *attr, char *buf)
2981 struct serial_struct tmp;
2982 struct tty_port *port = dev_get_drvdata(dev);
2984 uart_get_info(port, &tmp);
2985 return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2988 static ssize_t close_delay_show(struct device *dev,
2989 struct device_attribute *attr, char *buf)
2991 struct serial_struct tmp;
2992 struct tty_port *port = dev_get_drvdata(dev);
2994 uart_get_info(port, &tmp);
2995 return sprintf(buf, "%d\n", tmp.close_delay);
2998 static ssize_t closing_wait_show(struct device *dev,
2999 struct device_attribute *attr, char *buf)
3001 struct serial_struct tmp;
3002 struct tty_port *port = dev_get_drvdata(dev);
3004 uart_get_info(port, &tmp);
3005 return sprintf(buf, "%d\n", tmp.closing_wait);
3008 static ssize_t custom_divisor_show(struct device *dev,
3009 struct device_attribute *attr, char *buf)
3011 struct serial_struct tmp;
3012 struct tty_port *port = dev_get_drvdata(dev);
3014 uart_get_info(port, &tmp);
3015 return sprintf(buf, "%d\n", tmp.custom_divisor);
3018 static ssize_t io_type_show(struct device *dev,
3019 struct device_attribute *attr, char *buf)
3021 struct serial_struct tmp;
3022 struct tty_port *port = dev_get_drvdata(dev);
3024 uart_get_info(port, &tmp);
3025 return sprintf(buf, "%d\n", tmp.io_type);
3028 static ssize_t iomem_base_show(struct device *dev,
3029 struct device_attribute *attr, char *buf)
3031 struct serial_struct tmp;
3032 struct tty_port *port = dev_get_drvdata(dev);
3034 uart_get_info(port, &tmp);
3035 return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
3038 static ssize_t iomem_reg_shift_show(struct device *dev,
3039 struct device_attribute *attr, char *buf)
3041 struct serial_struct tmp;
3042 struct tty_port *port = dev_get_drvdata(dev);
3044 uart_get_info(port, &tmp);
3045 return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
3048 static ssize_t console_show(struct device *dev,
3049 struct device_attribute *attr, char *buf)
3051 struct tty_port *port = dev_get_drvdata(dev);
3052 struct uart_state *state = container_of(port, struct uart_state, port);
3053 struct uart_port *uport;
3054 bool console = false;
3056 mutex_lock(&port->mutex);
3057 uport = uart_port_check(state);
3059 console = uart_console_registered(uport);
3060 mutex_unlock(&port->mutex);
3062 return sprintf(buf, "%c\n", console ? 'Y' : 'N');
3065 static ssize_t console_store(struct device *dev,
3066 struct device_attribute *attr, const char *buf, size_t count)
3068 struct tty_port *port = dev_get_drvdata(dev);
3069 struct uart_state *state = container_of(port, struct uart_state, port);
3070 struct uart_port *uport;
3071 bool oldconsole, newconsole;
3074 ret = kstrtobool(buf, &newconsole);
3078 mutex_lock(&port->mutex);
3079 uport = uart_port_check(state);
3081 oldconsole = uart_console_registered(uport);
3082 if (oldconsole && !newconsole) {
3083 ret = unregister_console(uport->cons);
3084 } else if (!oldconsole && newconsole) {
3085 if (uart_console(uport)) {
3086 uport->console_reinit = 1;
3087 register_console(uport->cons);
3095 mutex_unlock(&port->mutex);
3097 return ret < 0 ? ret : count;
3100 static DEVICE_ATTR_RO(uartclk);
3101 static DEVICE_ATTR_RO(type);
3102 static DEVICE_ATTR_RO(line);
3103 static DEVICE_ATTR_RO(port);
3104 static DEVICE_ATTR_RO(irq);
3105 static DEVICE_ATTR_RO(flags);
3106 static DEVICE_ATTR_RO(xmit_fifo_size);
3107 static DEVICE_ATTR_RO(close_delay);
3108 static DEVICE_ATTR_RO(closing_wait);
3109 static DEVICE_ATTR_RO(custom_divisor);
3110 static DEVICE_ATTR_RO(io_type);
3111 static DEVICE_ATTR_RO(iomem_base);
3112 static DEVICE_ATTR_RO(iomem_reg_shift);
3113 static DEVICE_ATTR_RW(console);
3115 static struct attribute *tty_dev_attrs[] = {
3116 &dev_attr_uartclk.attr,
3117 &dev_attr_type.attr,
3118 &dev_attr_line.attr,
3119 &dev_attr_port.attr,
3121 &dev_attr_flags.attr,
3122 &dev_attr_xmit_fifo_size.attr,
3123 &dev_attr_close_delay.attr,
3124 &dev_attr_closing_wait.attr,
3125 &dev_attr_custom_divisor.attr,
3126 &dev_attr_io_type.attr,
3127 &dev_attr_iomem_base.attr,
3128 &dev_attr_iomem_reg_shift.attr,
3129 &dev_attr_console.attr,
3133 static const struct attribute_group tty_dev_attr_group = {
3134 .attrs = tty_dev_attrs,
3138 * serial_core_add_one_port - attach a driver-defined port structure
3139 * @drv: pointer to the uart low level driver structure for this port
3140 * @uport: uart port structure to use for this port.
3142 * Context: task context, might sleep
3144 * This allows the driver @drv to register its own uart_port structure with the
3145 * core driver. The main purpose is to allow the low level uart drivers to
3146 * expand uart_port, rather than having yet more levels of structures.
3147 * Caller must hold port_mutex.
3149 static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *uport)
3151 struct uart_state *state;
3152 struct tty_port *port;
3154 struct device *tty_dev;
3157 if (uport->line >= drv->nr)
3160 state = drv->state + uport->line;
3161 port = &state->port;
3163 mutex_lock(&port->mutex);
3164 if (state->uart_port) {
3169 /* Link the port to the driver state table and vice versa */
3170 atomic_set(&state->refcount, 1);
3171 init_waitqueue_head(&state->remove_wait);
3172 state->uart_port = uport;
3173 uport->state = state;
3175 state->pm_state = UART_PM_STATE_UNDEFINED;
3176 uport->cons = drv->cons;
3177 uport->minor = drv->tty_driver->minor_start + uport->line;
3178 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
3179 drv->tty_driver->name_base + uport->line);
3186 * If this port is in use as a console then the spinlock is already
3189 if (!uart_console_registered(uport))
3190 uart_port_spin_lock_init(uport);
3192 if (uport->cons && uport->dev)
3193 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
3195 tty_port_link_device(port, drv->tty_driver, uport->line);
3196 uart_configure_port(drv, state, uport);
3198 port->console = uart_console(uport);
3201 if (uport->attr_group)
3204 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
3206 if (!uport->tty_groups) {
3210 uport->tty_groups[0] = &tty_dev_attr_group;
3211 if (uport->attr_group)
3212 uport->tty_groups[1] = uport->attr_group;
3215 * Register the port whether it's detected or not. This allows
3216 * setserial to be used to alter this port's parameters.
3218 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
3219 uport->line, uport->dev, &uport->port_dev->dev, port,
3221 if (!IS_ERR(tty_dev)) {
3222 device_set_wakeup_capable(tty_dev, 1);
3224 dev_err(uport->dev, "Cannot register tty device on line %d\n",
3229 mutex_unlock(&port->mutex);
3235 * serial_core_remove_one_port - detach a driver defined port structure
3236 * @drv: pointer to the uart low level driver structure for this port
3237 * @uport: uart port structure for this port
3239 * Context: task context, might sleep
3241 * This unhooks (and hangs up) the specified port structure from the core
3242 * driver. No further calls will be made to the low-level code for this port.
3243 * Caller must hold port_mutex.
3245 static void serial_core_remove_one_port(struct uart_driver *drv,
3246 struct uart_port *uport)
3248 struct uart_state *state = drv->state + uport->line;
3249 struct tty_port *port = &state->port;
3250 struct uart_port *uart_port;
3251 struct tty_struct *tty;
3253 mutex_lock(&port->mutex);
3254 uart_port = uart_port_check(state);
3255 if (uart_port != uport)
3256 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
3260 mutex_unlock(&port->mutex);
3263 mutex_unlock(&port->mutex);
3266 * Remove the devices from the tty layer
3268 tty_port_unregister_device(port, drv->tty_driver, uport->line);
3270 tty = tty_port_tty_get(port);
3272 tty_vhangup(port->tty);
3277 * If the port is used as a console, unregister it
3279 if (uart_console(uport))
3280 unregister_console(uport->cons);
3283 * Free the port IO and memory resources, if any.
3285 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3286 uport->ops->release_port(uport);
3287 kfree(uport->tty_groups);
3291 * Indicate that there isn't a port here anymore.
3293 uport->type = PORT_UNKNOWN;
3294 uport->port_dev = NULL;
3296 mutex_lock(&port->mutex);
3297 WARN_ON(atomic_dec_return(&state->refcount) < 0);
3298 wait_event(state->remove_wait, !atomic_read(&state->refcount));
3299 state->uart_port = NULL;
3300 mutex_unlock(&port->mutex);
3304 * uart_match_port - are the two ports equivalent?
3305 * @port1: first port
3306 * @port2: second port
3308 * This utility function can be used to determine whether two uart_port
3309 * structures describe the same port.
3311 bool uart_match_port(const struct uart_port *port1,
3312 const struct uart_port *port2)
3314 if (port1->iotype != port2->iotype)
3317 switch (port1->iotype) {
3319 return port1->iobase == port2->iobase;
3321 return port1->iobase == port2->iobase &&
3322 port1->hub6 == port2->hub6;
3329 return port1->mapbase == port2->mapbase;
3334 EXPORT_SYMBOL(uart_match_port);
3336 static struct serial_ctrl_device *
3337 serial_core_get_ctrl_dev(struct serial_port_device *port_dev)
3339 struct device *dev = &port_dev->dev;
3341 return to_serial_base_ctrl_device(dev->parent);
3345 * Find a registered serial core controller device if one exists. Returns
3346 * the first device matching the ctrl_id. Caller must hold port_mutex.
3348 static struct serial_ctrl_device *serial_core_ctrl_find(struct uart_driver *drv,
3349 struct device *phys_dev,
3352 struct uart_state *state;
3355 lockdep_assert_held(&port_mutex);
3357 for (i = 0; i < drv->nr; i++) {
3358 state = drv->state + i;
3359 if (!state->uart_port || !state->uart_port->port_dev)
3362 if (state->uart_port->dev == phys_dev &&
3363 state->uart_port->ctrl_id == ctrl_id)
3364 return serial_core_get_ctrl_dev(state->uart_port->port_dev);
3370 static struct serial_ctrl_device *serial_core_ctrl_device_add(struct uart_port *port)
3372 return serial_base_ctrl_add(port, port->dev);
3375 static int serial_core_port_device_add(struct serial_ctrl_device *ctrl_dev,
3376 struct uart_port *port)
3378 struct serial_port_device *port_dev;
3380 port_dev = serial_base_port_add(port, ctrl_dev);
3381 if (IS_ERR(port_dev))
3382 return PTR_ERR(port_dev);
3384 port->port_dev = port_dev;
3390 * Initialize a serial core port device, and a controller device if needed.
3392 int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
3394 struct serial_ctrl_device *ctrl_dev, *new_ctrl_dev = NULL;
3397 mutex_lock(&port_mutex);
3400 * Prevent serial_port_runtime_resume() from trying to use the port
3401 * until serial_core_add_one_port() has completed
3403 port->flags |= UPF_DEAD;
3405 /* Inititalize a serial core controller device if needed */
3406 ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
3408 new_ctrl_dev = serial_core_ctrl_device_add(port);
3409 if (IS_ERR(new_ctrl_dev)) {
3410 ret = PTR_ERR(new_ctrl_dev);
3413 ctrl_dev = new_ctrl_dev;
3417 * Initialize a serial core port device. Tag the port dead to prevent
3418 * serial_port_runtime_resume() trying to do anything until port has
3419 * been registered. It gets cleared by serial_core_add_one_port().
3421 ret = serial_core_port_device_add(ctrl_dev, port);
3423 goto err_unregister_ctrl_dev;
3425 ret = serial_core_add_one_port(drv, port);
3427 goto err_unregister_port_dev;
3429 port->flags &= ~UPF_DEAD;
3431 mutex_unlock(&port_mutex);
3435 err_unregister_port_dev:
3436 serial_base_port_device_remove(port->port_dev);
3438 err_unregister_ctrl_dev:
3439 serial_base_ctrl_device_remove(new_ctrl_dev);
3442 mutex_unlock(&port_mutex);
3448 * Removes a serial core port device, and the related serial core controller
3449 * device if the last instance.
3451 void serial_core_unregister_port(struct uart_driver *drv, struct uart_port *port)
3453 struct device *phys_dev = port->dev;
3454 struct serial_port_device *port_dev = port->port_dev;
3455 struct serial_ctrl_device *ctrl_dev = serial_core_get_ctrl_dev(port_dev);
3456 int ctrl_id = port->ctrl_id;
3458 mutex_lock(&port_mutex);
3460 port->flags |= UPF_DEAD;
3462 serial_core_remove_one_port(drv, port);
3464 /* Note that struct uart_port *port is no longer valid at this point */
3465 serial_base_port_device_remove(port_dev);
3467 /* Drop the serial core controller device if no ports are using it */
3468 if (!serial_core_ctrl_find(drv, phys_dev, ctrl_id))
3469 serial_base_ctrl_device_remove(ctrl_dev);
3471 mutex_unlock(&port_mutex);
3475 * uart_handle_dcd_change - handle a change of carrier detect state
3476 * @uport: uart_port structure for the open port
3477 * @active: new carrier detect status
3479 * Caller must hold uport->lock.
3481 void uart_handle_dcd_change(struct uart_port *uport, bool active)
3483 struct tty_port *port = &uport->state->port;
3484 struct tty_struct *tty = port->tty;
3485 struct tty_ldisc *ld;
3487 lockdep_assert_held_once(&uport->lock);
3490 ld = tty_ldisc_ref(tty);
3492 if (ld->ops->dcd_change)
3493 ld->ops->dcd_change(tty, active);
3494 tty_ldisc_deref(ld);
3498 uport->icount.dcd++;
3500 if (uart_dcd_enabled(uport)) {
3502 wake_up_interruptible(&port->open_wait);
3507 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3510 * uart_handle_cts_change - handle a change of clear-to-send state
3511 * @uport: uart_port structure for the open port
3512 * @active: new clear-to-send status
3514 * Caller must hold uport->lock.
3516 void uart_handle_cts_change(struct uart_port *uport, bool active)
3518 lockdep_assert_held_once(&uport->lock);
3520 uport->icount.cts++;
3522 if (uart_softcts_mode(uport)) {
3523 if (uport->hw_stopped) {
3525 uport->hw_stopped = false;
3526 uport->ops->start_tx(uport);
3527 uart_write_wakeup(uport);
3531 uport->hw_stopped = true;
3532 uport->ops->stop_tx(uport);
3538 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3541 * uart_insert_char - push a char to the uart layer
3543 * User is responsible to call tty_flip_buffer_push when they are done with
3546 * @port: corresponding port
3547 * @status: state of the serial port RX buffer (LSR for 8250)
3548 * @overrun: mask of overrun bits in @status
3549 * @ch: character to push
3550 * @flag: flag for the character (see TTY_NORMAL and friends)
3552 void uart_insert_char(struct uart_port *port, unsigned int status,
3553 unsigned int overrun, u8 ch, u8 flag)
3555 struct tty_port *tport = &port->state->port;
3557 if ((status & port->ignore_status_mask & ~overrun) == 0)
3558 if (tty_insert_flip_char(tport, ch, flag) == 0)
3559 ++port->icount.buf_overrun;
3562 * Overrun is special. Since it's reported immediately,
3563 * it doesn't affect the current character.
3565 if (status & ~port->ignore_status_mask & overrun)
3566 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3567 ++port->icount.buf_overrun;
3569 EXPORT_SYMBOL_GPL(uart_insert_char);
3571 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3572 static const u8 sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3574 static void uart_sysrq_on(struct work_struct *w)
3576 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3578 sysrq_toggle_support(1);
3579 pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3580 sysrq_toggle_seq_len, sysrq_toggle_seq);
3582 static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3585 * uart_try_toggle_sysrq - Enables SysRq from serial line
3586 * @port: uart_port structure where char(s) after BREAK met
3587 * @ch: new character in the sequence after received BREAK
3589 * Enables magic SysRq when the required sequence is met on port
3590 * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3592 * Returns: %false if @ch is out of enabling sequence and should be
3593 * handled some other way, %true if @ch was consumed.
3595 bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch)
3597 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3599 if (!sysrq_toggle_seq_len)
3602 BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3603 if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3604 port->sysrq_seq = 0;
3608 if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3609 port->sysrq = jiffies + SYSRQ_TIMEOUT;
3613 schedule_work(&sysrq_enable_work);
3618 EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3622 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3623 * @port: uart device's target port
3625 * This function implements the device tree binding described in
3626 * Documentation/devicetree/bindings/serial/rs485.txt.
3628 int uart_get_rs485_mode(struct uart_port *port)
3630 struct serial_rs485 *rs485conf = &port->rs485;
3631 struct device *dev = port->dev;
3632 enum gpiod_flags dflags;
3633 struct gpio_desc *desc;
3637 if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
3640 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3643 rs485conf->delay_rts_before_send = rs485_delay[0];
3644 rs485conf->delay_rts_after_send = rs485_delay[1];
3646 rs485conf->delay_rts_before_send = 0;
3647 rs485conf->delay_rts_after_send = 0;
3650 uart_sanitize_serial_rs485_delays(port, rs485conf);
3653 * Clear full-duplex and enabled flags, set RTS polarity to active high
3654 * to get to a defined state with the following properties:
3656 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3657 SER_RS485_TERMINATE_BUS |
3658 SER_RS485_RTS_AFTER_SEND);
3659 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3661 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3662 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3664 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3665 rs485conf->flags |= SER_RS485_ENABLED;
3667 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3668 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3669 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3673 * Disabling termination by default is the safe choice: Else if many
3674 * bus participants enable it, no communication is possible at all.
3675 * Works fine for short cables and users may enable for longer cables.
3677 desc = devm_gpiod_get_optional(dev, "rs485-term", GPIOD_OUT_LOW);
3679 return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-term-gpios\n");
3680 port->rs485_term_gpio = desc;
3681 if (port->rs485_term_gpio)
3682 port->rs485_supported.flags |= SER_RS485_TERMINATE_BUS;
3684 dflags = (rs485conf->flags & SER_RS485_RX_DURING_TX) ?
3685 GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
3686 desc = devm_gpiod_get_optional(dev, "rs485-rx-during-tx", dflags);
3688 return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-rx-during-tx-gpios\n");
3689 port->rs485_rx_during_tx_gpio = desc;
3690 if (port->rs485_rx_during_tx_gpio)
3691 port->rs485_supported.flags |= SER_RS485_RX_DURING_TX;
3695 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3697 /* Compile-time assertions for serial_rs485 layout */
3698 static_assert(offsetof(struct serial_rs485, padding) ==
3699 (offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));
3700 static_assert(offsetof(struct serial_rs485, padding1) ==
3701 offsetof(struct serial_rs485, padding[1]));
3702 static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) ==
3703 sizeof(struct serial_rs485));
3705 MODULE_DESCRIPTION("Serial driver core");
3706 MODULE_LICENSE("GPL");