Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751370Ab2KPDF6 (ORCPT ); Thu, 15 Nov 2012 22:05:58 -0500 Received: from mga01.intel.com ([192.55.52.88]:64158 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751142Ab2KPDF5 (ORCPT ); Thu, 15 Nov 2012 22:05:57 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.83,261,1352102400"; d="scan'208";a="247785719" Subject: [PATCH] serial: ifx6x60: ifx_spi_write don't need to do mrdy_assert when fifo is not empty. From: Jun Chen To: Alan Cox Cc: Jun Chen , Bi Chao , serial , "russ.gorby" , linux-kernel@vger.kernel.org, fengguang.wu@intel.com, gregkh@linuxfoundation.org Content-Type: text/plain; charset="UTF-8" Date: Fri, 16 Nov 2012 06:08:37 -0500 Message-ID: <1353064117.24092.4.camel@chenjun-workstation> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1520 Lines: 45 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 | 14 +++++++++++--- 1 files changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/ifx6x60.c b/drivers/tty/serial/ifx6x60.c index 5b9bc19..aa01989 100644 --- a/drivers/tty/serial/ifx6x60.c +++ b/drivers/tty/serial/ifx6x60.c @@ -469,9 +469,17 @@ 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); + int tx_count; + 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); + 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/