From patchwork Thu Jul 29 08:46:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "zhiyong.tao" X-Patchwork-Id: 12408125 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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 0E70EC4338F for ; Thu, 29 Jul 2021 08:52:43 +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 C71B361040 for ; Thu, 29 Jul 2021 08:52:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org C71B361040 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=mediatek.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=YD0yR7uTGjQJux+4+FVKX+8HcMhK3qHYMJPHm94jZUg=; b=fXW9cpEkxEC8c3 2ne1ZVzu97Wgvlc/6OagkTyMnxgZQI6cWdRCbwkbkqkIu0x/kbQgtY3us5ffND6lcTqgdPwsbTckV D19Wq4E9BI15MMJVAWBFGnsZDUGoetTv18A1eHJebG3obt1xNA7qq9pBjh4ENhbfBZuwVCrguCuZI GTxmc80ayKFinz5QkRl2pYmkD3OQmN84bYI814Hx472kSIHGFiLbAI+LwK58Ih5EWA78VviMYtsGp OcHouvoIFBl4/sTgwT6irJ0GzFevIrAtBUwqWKlcXT9Tawql02St4ez3smGtFV0XMEfQpznzeZgc4 LSR5blt4zUs5MrKyOgKA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m91kg-003YQL-8t; Thu, 29 Jul 2021 08:50:50 +0000 Received: from mailgw01.mediatek.com ([216.200.240.184]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1m91kP-003YLg-13; Thu, 29 Jul 2021 08:50:34 +0000 X-UUID: 957b2916f4084bc48c8a7dc6e370bdee-20210729 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Transfer-Encoding:Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:CC:To:From; bh=XJ33CG0m+svLNFoWArLdQSxJE17P5OlOxX7g0fXTCkU=; b=Y8RIPEtwV64pjd1iUMeBhD+R2ZEAIU9N0iZOHb1F5HUCw6+3U98pNbWDeVe5ARt9pUweraKJEYWgsGrcCuTM3RngieIc/QwUbplf+cWGqmXImgCHq0fgZMGrqW0ttUAcpgWeolo8rGXhDrAY9mBAA/uh6OEn0yfAZnOhUllK6+g=; X-UUID: 957b2916f4084bc48c8a7dc6e370bdee-20210729 Received: from mtkcas66.mediatek.inc [(172.29.193.44)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 125147074; Thu, 29 Jul 2021 01:50:27 -0700 Received: from MTKMBS07N2.mediatek.inc (172.21.101.141) by MTKMBS62N1.mediatek.inc (172.29.193.41) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 29 Jul 2021 01:47:15 -0700 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkmbs07n2.mediatek.inc (172.21.101.141) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 29 Jul 2021 16:47:14 +0800 Received: from localhost.localdomain (10.17.3.153) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Thu, 29 Jul 2021 16:47:13 +0800 From: Zhiyong Tao To: , , , , CC: , , , , , , , , , , , Subject: [PATCH v2 1/1] serial: 8250_mtk: fix uart corruption issue when rx power off Date: Thu, 29 Jul 2021 16:46:40 +0800 Message-ID: <20210729084640.17613-2-zhiyong.tao@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20210729084640.17613-1-zhiyong.tao@mediatek.com> References: <20210729084640.17613-1-zhiyong.tao@mediatek.com> MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210729_015033_164701_CFA99E7D X-CRM114-Status: GOOD ( 11.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Fix uart corruption issue when rx power off. Add spin lock in mtk8250_dma_rx_complete function in APDMA mode. when uart is used as a communication port with external device(GPS). when external device(GPS) power off, the power of rx pin is also from 1.8v to 0v. Even if there is not any data in rx. But uart rx pin can capture the data "0". If uart don't receive any data in specified cycle, uart will generates BI(Break interrupt) interrupt. If external device(GPS) power off, we found that BI interrupt appeared continuously and very frequently. When uart interrupt type is BI, uart IRQ handler(8250 framwork API:serial8250_handle_irq) will push data to tty buffer. mtk8250_dma_rx_complete is a task of mtk_uart_apdma_rx_handler. mtk8250_dma_rx_complete priority is lower than uart irq handler(serial8250_handle_irq). if we are in process of mtk8250_dma_rx_complete, uart appear BI interrupt:1)serial8250_handle_irq will priority execution.2)it may cause write tty buffer conflict in mtk8250_dma_rx_complete. So the spin lock protect the rx receive data process is not break. Signed-off-by: Zhiyong Tao --- drivers/tty/serial/8250/8250_mtk.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c index f7d3023f860f..fb65dc601b23 100644 --- a/drivers/tty/serial/8250/8250_mtk.c +++ b/drivers/tty/serial/8250/8250_mtk.c @@ -93,10 +93,13 @@ static void mtk8250_dma_rx_complete(void *param) struct dma_tx_state state; int copied, total, cnt; unsigned char *ptr; + unsigned long flags; if (data->rx_status == DMA_RX_SHUTDOWN) return; + spin_lock_irqsave(&up->port.lock, flags); + dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); total = dma->rx_size - state.residue; cnt = total; @@ -120,6 +123,8 @@ static void mtk8250_dma_rx_complete(void *param) tty_flip_buffer_push(tty_port); mtk8250_rx_dma(up); + + spin_unlock_irqrestore(&up->port.lock, flags); } static void mtk8250_rx_dma(struct uart_8250_port *up)