From 654ee49b7e0883e660be6e6e20876fc4cbdaadd1 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Thu, 10 Jun 2021 11:02:44 +0200 Subject: [PATCH] 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 Cc: Johan Hovold Reviewed-by: Andy Shevchenko Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210610090247.2593-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 30 +++------------------------ drivers/tty/tty_ioctl.c | 45 ++++++++++++++++++++++++++++++++++++++++ include/linux/tty.h | 3 +++ 3 files changed, 51 insertions(+), 27 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 642e24d..69092de 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -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); diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c index 75885d5..507a25d 100644 --- a/drivers/tty/tty_ioctl.c +++ b/drivers/tty/tty_ioctl.c @@ -280,6 +280,51 @@ 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 * @new_termios: desired new value diff --git a/include/linux/tty.h b/include/linux/tty.h index 4c0c7ca..19dc109 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -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); -- 2.7.4