Commit 654ee49b authored by Jiri Slaby's avatar Jiri Slaby Committed by Greg Kroah-Hartman
Browse files

tty: make tty_get_{char,frame}_size available 



Many tty drivers contain code to compute bits count depending on termios
cflags. So extract this code from serial core to two separate tty helper
functions:
* tty_get_char_size -- only size of a character, without flags,
* tty_get_frame_size -- complete size of a frame including flags.

In the next patch, calls to these new functions replace many copies of
this code.

Note that we accept only cflag as a parameter. That's because some
callers like pch_uart_startup or sunsab_console_setup don't have at hand
termios which we could pass around.

Cc: Joe Perches <joe@perches.com>
Cc: Johan Hovold <johan@kernel.org>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210610090247.2593-1-jslaby@suse.cz


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fb524360

drivers/tty/serial/serial_core.c

+3 −27
Original line number Diff line number Diff line
@@ -334,39 +334,15 @@ void 
uart_update_timeout(struct uart_port *port, unsigned int cflag,

		    unsigned int baud)

{

	unsigned int bits;

	unsigned int size;



	/* byte size and parity */

	switch (cflag & CSIZE) {

	case CS5:

		bits = 7;

		break;

	case CS6:

		bits = 8;

		break;

	case CS7:

		bits = 9;

		break;

	default:

		bits = 10;

		break; /* CS8 */

	}



	if (cflag & CSTOPB)

		bits++;

	if (cflag & PARENB)

		bits++;



	/*

	 * The total number of bits to be transmitted in the fifo.

	 */

	bits = bits * port->fifosize;

	size = tty_get_frame_size(cflag) * port->fifosize;



	/*

	 * Figure the timeout to send the above number of bits.

	 * Add .02 seconds of slop

	 */

	port->timeout = (HZ * bits) / baud + HZ/50;

	port->timeout = (HZ * size) / baud + HZ/50;

}



EXPORT_SYMBOL(uart_update_timeout);

drivers/tty/tty_ioctl.c

+45 −0
Original line number Diff line number Diff line
@@ -279,6 +279,51 @@ int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b) 
}

EXPORT_SYMBOL(tty_termios_hw_change);



/**

 *	tty_get_char_size	-	get size of a character

 *	@cflag: termios cflag value

 *

 *	Get the size (in bits) of a character depending on @cflag's %CSIZE

 *	setting.

 */

unsigned char tty_get_char_size(unsigned int cflag)

{

	switch (cflag & CSIZE) {

	case CS5:

		return 5;

	case CS6:

		return 6;

	case CS7:

		return 7;

	case CS8:

	default:

		return 8;

	}

}

EXPORT_SYMBOL_GPL(tty_get_char_size);



/**

 *	tty_get_frame_size	-	get size of a frame

 *	@cflag: termios cflag value

 *

 *	Get the size (in bits) of a frame depending on @cflag's %CSIZE, %CSTOPB,

 *	and %PARENB setting. The result is a sum of character size, start and

 *	stop bits -- one bit each -- second stop bit (if set), and parity bit

 *	(if set).

 */

unsigned char tty_get_frame_size(unsigned int cflag)

{

	unsigned char bits = 2 + tty_get_char_size(cflag);



	if (cflag & CSTOPB)

		bits++;

	if (cflag & PARENB)

		bits++;



	return bits;

}

EXPORT_SYMBOL_GPL(tty_get_frame_size);



/**

 *	tty_set_termios		-	update termios values

 *	@tty: tty to update

include/linux/tty.h

+3 −0
Original line number Diff line number Diff line
@@ -495,6 +495,9 @@ static inline speed_t tty_get_baud_rate(struct tty_struct *tty) 
	return tty_termios_baud_rate(&tty->termios);

}



unsigned char tty_get_char_size(unsigned int cflag);

unsigned char tty_get_frame_size(unsigned int cflag);



extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);

extern int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);

extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);