From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDD94C3A5A6 for ; Thu, 19 Sep 2019 10:26:57 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id ADBC221907 for ; Thu, 19 Sep 2019 10:26:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="CddWsE8M" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ADBC221907 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=emlix.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=w4FlfBQRBqSonBx5sxy0LuUA3wli9U0/Sc6Wi6fzbEg=; b=CddWsE8M6ggTcP /dKfb486gxsime0MFCqzttMotgHkeWzZMbLiC2FHY0O98a6QSICA8vRx0rllZEuvFD4N9qDDCDwcd p/YD4kFgOcberRN6He3Ad7AER92X8mBKPgMzRX6rMlXnGk2JG7T3ngSMFa8qq8/WG1lhRV6zDswx6 ITgqXrIghR7oONX5mhly+PL8qCPO6GekN+9Pt7C6hCpPIAKgG+FDPPQyZvmiQuRTe2kbH+u3xJMCj HW4UJCZ8g1HwMYJK3wdrVc/ZtWEcU+tID7ubCHrDx5z7TCKa3+vk0/BqMa658GEcqWvMOXwXDj2rs lQ2obhRmvdj86u1v8SDw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iAteF-0003v3-NF; Thu, 19 Sep 2019 10:26:51 +0000 Received: from mx1.emlix.com ([188.40.240.192]) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1iAteC-0003uO-LU for linux-arm-kernel@lists.infradead.org; Thu, 19 Sep 2019 10:26:50 +0000 Received: from mailer.emlix.com (unknown [81.20.119.6]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.emlix.com (Postfix) with ESMTPS id EF3CC603CA; Thu, 19 Sep 2019 12:26:46 +0200 (CEST) From: Philipp Puschmann To: linux-kernel@vger.kernel.org Subject: [PATCH v2] serial: imx: adapt rx buffer and dma periods Date: Thu, 19 Sep 2019 12:26:28 +0200 Message-Id: <20190919102628.23621-1-philipp.puschmann@emlix.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190919_032648_851388_5B532E27 X-CRM114-Status: GOOD ( 10.22 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: festevam@gmail.com, fugang.duan@nxp.com, linux-serial@vger.kernel.org, gregkh@linuxfoundation.org, s.hauer@pengutronix.de, linux-imx@nxp.com, kernel@pengutronix.de, jslaby@suse.com, Philipp Puschmann , yibin.gong@nxp.com, shawnguo@kernel.org, linux-arm-kernel@lists.infradead.org, l.stach@pengutronix.de Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Using only 4 DMA periods for UART RX is very few if we have a high frequency of small transfers - like in our case using Bluetooth with many small packets via UART - causing many dma transfers but in each only filling a fraction of a single buffer. Such a case may lead to the situation that DMA RX transfer is triggered but no free buffer is available. While we have addressed the dma handling already with "dmaengine: imx-sdma: fix dma freezes" we still want to avoid UART RX FIFO overrun. So we decrease the size of the buffers and increase their number and the total buffer size. Signed-off-by: Philipp Puschmann Reviewed-by: Lucas Stach --- Changelog v2: - split this patch from series "Fix UART DMA freezes for iMX6" - add Reviewed-by tag drivers/tty/serial/imx.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 87c58f9f6390..51dc19833eab 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -1034,8 +1034,6 @@ static void imx_uart_timeout(struct timer_list *t) } } -#define RX_BUF_SIZE (PAGE_SIZE) - /* * There are two kinds of RX DMA interrupts(such as in the MX6Q): * [1] the RX DMA buffer is full. @@ -1118,7 +1116,8 @@ static void imx_uart_dma_rx_callback(void *data) } /* RX DMA buffer periods */ -#define RX_DMA_PERIODS 4 +#define RX_DMA_PERIODS 16 +#define RX_BUF_SIZE (PAGE_SIZE / 4) static int imx_uart_start_rx_dma(struct imx_port *sport) { -- 2.23.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel