From patchwork Fri Nov 28 00:23:25 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Agner X-Patchwork-Id: 5400441 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 96D6BBEEA8 for ; Fri, 28 Nov 2014 00:26:39 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2E4CA20138 for ; Fri, 28 Nov 2014 00:26:38 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 49B492012E for ; Fri, 28 Nov 2014 00:26:37 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Xu9MU-0007Fy-Fq; Fri, 28 Nov 2014 00:24:38 +0000 Received: from mail.kmu-office.ch ([2a02:418:6a02::a2]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Xu9Lj-0006rX-BV for linux-arm-kernel@lists.infradead.org; Fri, 28 Nov 2014 00:23:53 +0000 Received: from trochilidae.agner.local (195-226-23-137.pool.cyberlink.ch [195.226.23.137]) by mail.kmu-office.ch (Postfix) with ESMTPSA id D4E8E5E35A6; Fri, 28 Nov 2014 01:23:03 +0100 (CET) From: Stefan Agner To: gregkh@linuxfoundation.org Subject: [PATCH 4/4] serial: fsl_lpuart: update RX timer on successful DMA transfer Date: Fri, 28 Nov 2014 01:23:25 +0100 Message-Id: <1417134205-4400-5-git-send-email-stefan@agner.ch> X-Mailer: git-send-email 2.1.3 In-Reply-To: <1417134205-4400-1-git-send-email-stefan@agner.ch> References: <1417134205-4400-1-git-send-email-stefan@agner.ch> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141127_162351_622169_1E3460DC X-CRM114-Status: UNSURE ( 9.42 ) X-CRM114-Notice: Please train this message. X-Spam-Score: 0.0 (/) Cc: linux-kernel@vger.kernel.org, stefan@agner.ch, linux-serial@vger.kernel.org, jingchang.lu@freescale.com, shawn.guo@linaro.org, jslaby@suse.cz, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_LOW, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP To end a DMA transfer which did not consume a whole buffer (e.g. one character only), a RX timer is used. When lots of data are received the DMA transfer will complete and setup another DMA transfer, which in turn might complete again. In this cases, it is not necessary to abort the DMA transfers using the RX timer. This change pushes the RX timer timeout into the future each time a DMA transfer completed. Aborting the DMA was not very harmful, since the next received character lead to setup of another RX DMA. Signed-off-by: Stefan Agner --- drivers/tty/serial/fsl_lpuart.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index be9ccdf..b1c1589 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -462,6 +462,7 @@ static void lpuart_dma_rx_complete(void *arg) unsigned long flags; async_tx_ack(sport->dma_rx_desc); + mod_timer(&sport->lpuart_timer, jiffies + sport->dma_rx_timeout); spin_lock_irqsave(&sport->port.lock, flags);