serial: sh-sci: Fix setting SCSCR_TIE while transferring data
commitbe8c93469b723a77168953bced05bc33048f5af5
authorHoan Nguyen An <na-hoan@jinso.co.jp>
Mon, 18 Mar 2019 09:26:32 +0000 (18 18:26 +0900)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 3 Apr 2019 04:25:18 +0000 (3 06:25 +0200)
treed5c6a0a45aae4280580716662ede202056ba0b91
parent0d42abfacfcedc695964d655495c0dbb34e22647
serial: sh-sci: Fix setting SCSCR_TIE while transferring data

commit 93bcefd4c6bad4c69dbc4edcd3fbf774b24d930d upstream.

We disable transmission interrupt (clear SCSCR_TIE) after all data has been transmitted
(if uart_circ_empty(xmit)). While transmitting, if the data is still in the tty buffer,
re-enable the SCSCR_TIE bit, which was done at sci_start_tx().
This is unnecessary processing, wasting CPU operation if the data transmission length is large.
And further, transmit end, FIFO empty bits disabling have also been performed in the step above.

Signed-off-by: Hoan Nguyen An <na-hoan@jinso.co.jp>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/serial/sh-sci.c