diff options
| author | Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> | 2022-06-13 14:39:05 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-27 14:34:45 +0200 |
| commit | f9008285bb69e4713918a665250ab2d356b731ba (patch) | |
| tree | dd37d533edbf6b5fb962959ecc1484054e932903 /include/linux/serial_core.h | |
| parent | ab24a01b276508dc884761bcb8e2759c36702377 (diff) | |
serial: Drop timeout from uart_port
Since commit 31f6bd7fad3b ("serial: Store character timing information
to uart_port"), per frame timing information is available on uart_port.
Uart port's timeout can be derived from frame_time by multiplying with
fifosize.
Most callers of uart_poll_timeout are not made under port's lock. To be
on the safe side, make sure frame_time is only accessed once. As
fifo_size is effectively a constant, it shouldn't cause any issues.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220613113905.22962-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/serial_core.h')
| -rw-r--r-- | include/linux/serial_core.h | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 8032ffa741ed..faaf2372c60d 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -232,7 +232,6 @@ struct uart_port { int hw_stopped; /* sw-assisted CTS flow state */ unsigned int mctrl; /* current modem ctrl settings */ - unsigned int timeout; /* character-based timeout */ unsigned int frame_time; /* frame timing in ns */ unsigned int type; /* port type */ const struct uart_ops *ops; @@ -335,10 +334,23 @@ unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios unsigned int max); unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud); +/* + * Calculates FIFO drain time. + */ +static inline unsigned long uart_fifo_timeout(struct uart_port *port) +{ + u64 fifo_timeout = (u64)READ_ONCE(port->frame_time) * port->fifosize; + + /* Add .02 seconds of slop */ + fifo_timeout += 20 * NSEC_PER_MSEC; + + return max(nsecs_to_jiffies(fifo_timeout), 1UL); +} + /* Base timer interval for polling */ static inline int uart_poll_timeout(struct uart_port *port) { - int timeout = port->timeout; + int timeout = uart_fifo_timeout(port); return timeout > 6 ? (timeout / 2 - 2) : 1; } |