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.
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: Johan Hovold <johan@xxxxxxxxxx>
---
[v2] simplified the code flow as suggested by Joe and Andy
[v3] redesign to have 2 functions as suggested by Johan.
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 642e24d6c475..69092deba11f 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 75885d502749..507a25d692bb 100644
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -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
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 4c0c7ca1d9a4..19dc1097e09c 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);
--
2.32.0
