serial: Create uart_xmit_advance()

commit e77cab77f2cb3a1ca2ba8df4af45bb35617ac16d upstream.

A very common pattern in the drivers is to advance xmit tail
index and do bookkeeping of Tx'ed characters. Create
uart_xmit_advance() to handle it.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220901143934.8850-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ilpo Järvinen 2022-09-01 17:39:32 +03:00 committed by Greg Kroah-Hartman
parent 1c9b1d0211
commit 3b5fa3abe0

View File

@ -306,6 +306,23 @@ struct uart_state {
/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS 256
/**
* uart_xmit_advance - Advance xmit buffer and account Tx'ed chars
* @up: uart_port structure describing the port
* @chars: number of characters sent
*
* This function advances the tail of circular xmit buffer by the number of
* @chars transmitted and handles accounting of transmitted bytes (into
* @up's icount.tx).
*/
static inline void uart_xmit_advance(struct uart_port *up, unsigned int chars)
{
struct circ_buf *xmit = &up->state->xmit;
xmit->tail = (xmit->tail + chars) & (UART_XMIT_SIZE - 1);
up->icount.tx += chars;
}
struct module;
struct tty_driver;