From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jun Chen Subject: [PATCH] serial: ifx6x60: ifx_spi_write don't need to do mrdy_assert when fifo is not empty Date: Wed, 07 Nov 2012 12:04:04 -0500 Message-ID: <1352307844.4332.63.camel@chenjun-workstation> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mga14.intel.com ([143.182.124.37]:37668 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751673Ab2KGJBb (ORCPT ); Wed, 7 Nov 2012 04:01:31 -0500 Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Alan Cox Cc: Bi Chao , serial , "russ.gorby" , Jun Chen This patch check whether the fifo lenth is empty before writing new data to fifo.If condition is true,ifx_spi_write need to trigger one mrdy_assert. If condition is false,the mrdy_assert will be trigger by the next ifx_spi_io. Cc: Bi Chao Signed-off-by: Chen Jun --- drivers/tty/serial/ifx6x60.c | 13 ++++++++++--- 1 files changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/ifx6x60.c b/drivers/tty/serial/ifx6x60.c index a688f8f..4a21f5e 100644 --- a/drivers/tty/serial/ifx6x60.c +++ b/drivers/tty/serial/ifx6x60.c @@ -520,9 +520,16 @@ static int ifx_spi_write(struct tty_struct *tty, const unsigned char *buf, { struct ifx_spi_device *ifx_dev = tty->driver_data; unsigned char *tmp_buf = (unsigned char *)buf; - int tx_count = kfifo_in_locked(&ifx_dev->tx_fifo, tmp_buf, count, - &ifx_dev->fifo_lock); - mrdy_assert(ifx_dev); + unsigned long flags; + bool is_fifo_empty; + + spin_lock_irqsave(&ifx_dev->fifo_lock, flags); + is_fifo_empty = kfifo_is_empty(&ifx_dev->tx_fifo); + int tx_count = kfifo_in(&ifx_dev->tx_fifo, tmp_buf, count); + spin_unlock_irqrestore(&ifx_dev->fifo_lock, flags); + if (is_fifo_empty) + mrdy_assert(ifx_dev); + return tx_count; } -- 1.7.4.1