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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 D7ED5C43387 for ; Mon, 7 Jan 2019 16:23:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B13D52147C for ; Mon, 7 Jan 2019 16:23:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729631AbfAGQX0 (ORCPT ); Mon, 7 Jan 2019 11:23:26 -0500 Received: from albert.telenet-ops.be ([195.130.137.90]:59598 "EHLO albert.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730168AbfAGQXZ (ORCPT ); Mon, 7 Jan 2019 11:23:25 -0500 Received: from ramsan ([84.194.111.163]) by albert.telenet-ops.be with bizsmtp id MUPM1z00V3XaVaC06UPM92; Mon, 07 Jan 2019 17:23:24 +0100 Received: from rox.of.borg ([192.168.97.57]) by ramsan with esmtp (Exim 4.90_1) (envelope-from ) id 1ggXgP-0008G1-FT; Mon, 07 Jan 2019 17:23:21 +0100 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1ggXgP-00043R-E7; Mon, 07 Jan 2019 17:23:21 +0100 From: Geert Uytterhoeven To: Greg Kroah-Hartman , Jiri Slaby Cc: Wolfram Sang , Ulrich Hecht , Yoshihiro Shimoda , Simon Horman , Yoshinori Sato , linux-serial@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-sh@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v5 3/4] serial: sh-sci: Fix fallback to PIO in sci_dma_rx_complete() Date: Mon, 7 Jan 2019 17:23:19 +0100 Message-Id: <20190107162320.15530-4-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190107162320.15530-1-geert+renesas@glider.be> References: <20190107162320.15530-1-geert+renesas@glider.be> Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org When submitting a DMA request fails in sci_dma_rx_complete(), the driver tries to fall back to PIO, but that does not work: no more data will be received, or the kernel will even crash. Fix this similar as in (but not identical to) sci_submit_rx(): - On SCIF, PIO cannot take over if any DMA transactions are pending, hence they must be terminated first. - All active cookies must be invalidated, else rx_timer_fn() may trigger a NULL pointer dereference. - Restarting the port is not needed, as it is already running, but serial port interrupts must be directed back from the DMA engine to the CPU. Signed-off-by: Geert Uytterhoeven --- v5: - Call new helpers sci_dma_rx_chan_invalidate() and sci_dma_rx_reenable_irq() instead of open-coding, v4: - No changes, v3: - Add missing definition of "u16 scr", - Move call to dmaengine_terminate_async() inside the spinlock, for symmetry with sci_submit_rx(), - Split in multiple patches. --- drivers/tty/serial/sh-sci.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 4d814c30c4189b56..891833315698b953 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1337,8 +1337,9 @@ static void sci_dma_rx_complete(void *arg) dev_warn(port->dev, "Failed submitting Rx DMA descriptor\n"); /* Switch to PIO */ spin_lock_irqsave(&port->lock, flags); - s->chan_rx = NULL; - sci_start_rx(port); + dmaengine_terminate_async(chan); + sci_dma_rx_chan_invalidate(s); + sci_dma_rx_reenable_irq(s); spin_unlock_irqrestore(&port->lock, flags); } -- 2.17.1