1 /* SPDX-License-Identifier: GPL-2.0-or-later */
5  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
24 	((port)->cons && (port)->cons->index == (port)->line)
36  * struct uart_ops -- interface between serial_core and the driver
57  *		- %TIOCM_RTS	RTS signal.
58  *		- %TIOCM_DTR	DTR signal.
59  *		- %TIOCM_OUT1	OUT1 signal.
60  *		- %TIOCM_OUT2	OUT2 signal.
61  *		- %TIOCM_LOOP	Set the port into loopback mode.
67  *	Locking: @port->lock taken.
77  *		- %TIOCM_CAR	state of DCD signal
78  *		- %TIOCM_CTS	state of CTS signal
79  *		- %TIOCM_DSR	state of DSR signal
80  *		- %TIOCM_RI	state of RI signal
87  *	Locking: @port->lock taken.
99  *	Locking: @port->lock taken.
107  *	Locking: @port->lock taken.
149  *	Locking: @port->lock taken.
157  *	Locking: @port->lock taken.
168  *	Locking: @port->lock taken.
178  *	Locking: caller holds tty_port->mutex
197  *	Drivers must not access @port->state once this call has completed.
210  *	This will be called whenever the @port->state->xmit circular buffer is
213  *	Locking: @port->lock taken.
221  *	Update @port->read_status_mask and @port->ignore_status_mask to
225  *	- %CSIZE - word size
226  *	- %CSTOPB - 2 stop bits
227  *	- %PARENB - parity enable
228  *	- %PARODD - odd parity (when %PARENB is in force)
229  *	- %ADDRB - address bit (changed through uart_port::rs485_config()).
230  *	- %CREAD - enable reception of characters (if not set, still receive
232  *	- %CRTSCTS - if set, enable CTS status change reporting.
233  *	- %CLOCAL - if not set, enable modem status change reporting.
237  *	- %INPCK - enable frame and parity error events to be passed to the TTY
239  *	- %BRKINT / %PARMRK - both of these enable break events to be passed to
241  *	- %IGNPAR - ignore parity and framing errors.
242  *	- %IGNBRK - ignore break errors. If %IGNPAR is also set, ignore overrun
260  *	Locking: caller holds tty_port->mutex
267  *	Documentation/driver-api/tty/tty_ldisc.rst.
269  *	Locking: caller holds tty_port->mutex
307  *	it should return -%EBUSY on failure.
317  *	@port->type should be set to the type found, or %PORT_UNKNOWN if no
352  *	Locking: %tty_mutex and tty_port->mutex taken.
475 #define UPIO_MEM		(SERIAL_IO_MEM)		/* driver-specific */
501 	 * The remaining bits are serial-core specific and not modifiable by
520 /* Port has hardware-assisted h/w flow control */
524 /* Port has hardware-assisted s/w flow control */
543 #error Change mask not equivalent to userspace-visible bit defines
559 	bool			hw_stopped;		/* sw-assisted CTS flow state */
593 	return up->serial_in(up, offset);  in serial_port_in()
598 	up->serial_out(up, offset, value);  in serial_port_out()
602  * enum uart_pm_state - power states for UARTs
634  * uart_xmit_advance - Advance xmit buffer and account Tx'ed chars
644 	struct circ_buf *xmit = &up->state->xmit;  in uart_xmit_advance()
646 	xmit->tail = (xmit->tail + chars) & (UART_XMIT_SIZE - 1);  in uart_xmit_advance()
647 	up->icount.tx += chars;  in uart_xmit_advance()
664 	 * touch these; they should be initialised to NULL
676 	struct circ_buf *xmit = &__port->state->xmit;			      \
679 	for (; (for_test) && (tx_ready); (for_post), __port->icount.tx++) {   \
680 		if (__port->x_char) {					      \
681 			(ch) = __port->x_char;				      \
683 			__port->x_char = 0;				      \
690 		(ch) = xmit->buf[xmit->tail];				      \
692 		xmit->tail = (xmit->tail + 1) % UART_XMIT_SIZE;		      \
702 			__port->ops->stop_tx(__port);			      \
709  * uart_port_tx_limited -- transmit helper for uart_port with count limiting
728  *    action before potential invocation of ops->stop_tx() happens. If the
731  * For all of them, @port->lock is held, interrupts are locally disabled and
737 			__count--);					      \
741  * uart_port_tx -- transmit helper for uart_port
767 	u64 fifo_timeout = (u64)READ_ONCE(port->frame_time) * port->fifosize;  in uart_fifo_timeout()
780 	return timeout > 6 ? (timeout / 2 - 2) : 1;  in uart_poll_timeout()
833 	return uart_console(port) && console_is_registered_locked(port->cons);  in uart_console_registered_locked()
838 	return uart_console(port) && console_is_registered(port->cons);  in uart_console_registered()
870 #define uart_circ_empty(circ)		((circ)->head == (circ)->tail)
871 #define uart_circ_clear(circ)		((circ)->head = (circ)->tail = 0)
874 	(CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
877 	(CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
881 	struct tty_struct *tty = port->state->port.tty;  in uart_tx_stopped()
882 	if ((tty && tty->flow.stopped) || port->hw_stopped)  in uart_tx_stopped()
889 	return !!(uport->status & UPSTAT_CTS_ENABLE);  in uart_cts_enabled()
896 	return ((uport->status & mask) == UPSTAT_CTS_ENABLE);  in uart_softcts_mode()
918 	if (!port->sysrq)  in uart_handle_sysrq_char()
921 	if (ch && time_before(jiffies, port->sysrq)) {  in uart_handle_sysrq_char()
924 			port->sysrq = 0;  in uart_handle_sysrq_char()
930 	port->sysrq = 0;  in uart_handle_sysrq_char()
937 	if (!port->sysrq)  in uart_prepare_sysrq_char()
940 	if (ch && time_before(jiffies, port->sysrq)) {  in uart_prepare_sysrq_char()
942 			port->sysrq_ch = ch;  in uart_prepare_sysrq_char()
943 			port->sysrq = 0;  in uart_prepare_sysrq_char()
949 	port->sysrq = 0;  in uart_prepare_sysrq_char()
958 	if (!port->has_sysrq) {  in uart_unlock_and_check_sysrq()
959 		spin_unlock(&port->lock);  in uart_unlock_and_check_sysrq()
963 	sysrq_ch = port->sysrq_ch;  in uart_unlock_and_check_sysrq()
964 	port->sysrq_ch = 0;  in uart_unlock_and_check_sysrq()
966 	spin_unlock(&port->lock);  in uart_unlock_and_check_sysrq()
977 	if (!port->has_sysrq) {  in uart_unlock_and_check_sysrq_irqrestore()
978 		spin_unlock_irqrestore(&port->lock, flags);  in uart_unlock_and_check_sysrq_irqrestore()
982 	sysrq_ch = port->sysrq_ch;  in uart_unlock_and_check_sysrq_irqrestore()
983 	port->sysrq_ch = 0;  in uart_unlock_and_check_sysrq_irqrestore()
985 	spin_unlock_irqrestore(&port->lock, flags);  in uart_unlock_and_check_sysrq_irqrestore()
1001 	spin_unlock(&port->lock);  in uart_unlock_and_check_sysrq()
1006 	spin_unlock_irqrestore(&port->lock, flags);  in uart_unlock_and_check_sysrq_irqrestore()
1015 	struct uart_state *state = port->state;  in uart_handle_break()
1017 	if (port->handle_break)  in uart_handle_break()
1018 		port->handle_break(port);  in uart_handle_break()
1021 	if (port->has_sysrq && uart_console(port)) {  in uart_handle_break()
1022 		if (!port->sysrq) {  in uart_handle_break()
1023 			port->sysrq = jiffies + SYSRQ_TIMEOUT;  in uart_handle_break()
1026 		port->sysrq = 0;  in uart_handle_break()
1029 	if (port->flags & UPF_SAK)  in uart_handle_break()
1030 		do_SAK(state->port.tty);  in uart_handle_break()
1035  *	UART_ENABLE_MS - determine if port should enable modem status irqs
1037 #define UART_ENABLE_MS(port,cflag)	((port)->flags & UPF_HARDPPS_CD || \