From patchwork Mon Dec 10 18:21:54 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 10722115 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B359D679F for ; Mon, 10 Dec 2018 18:22:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A7EDF29CA8 for ; Mon, 10 Dec 2018 18:22:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9BFA62ABAB; Mon, 10 Dec 2018 18:22:02 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3B2AA2AB5D for ; Mon, 10 Dec 2018 18:22:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728521AbeLJSWB (ORCPT ); Mon, 10 Dec 2018 13:22:01 -0500 Received: from albert.telenet-ops.be ([195.130.137.90]:39354 "EHLO albert.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727264AbeLJSV7 (ORCPT ); Mon, 10 Dec 2018 13:21:59 -0500 Received: from ramsan ([84.194.111.163]) by albert.telenet-ops.be with bizsmtp id AJMw1z0013XaVaC06JMwnt; Mon, 10 Dec 2018 19:21:57 +0100 Received: from rox.of.borg ([192.168.97.57]) by ramsan with esmtp (Exim 4.90_1) (envelope-from ) id 1gWQBn-00021W-U6; Mon, 10 Dec 2018 19:21:55 +0100 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1gWQBn-0005JL-Rw; Mon, 10 Dec 2018 19:21:55 +0100 From: Geert Uytterhoeven To: Greg Kroah-Hartman , Jiri Slaby Cc: Ulrich Hecht , Wolfram Sang , Yoshihiro Shimoda , Yoshinori Sato , linux-renesas-soc@vger.kernel.org, linux-sh@vger.kernel.org, linux-serial@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v3 4/4] serial: sh-sci: Fix fallback to PIO in sci_dma_rx_complete() Date: Mon, 10 Dec 2018 19:21:54 +0100 Message-Id: <20181210182154.20357-5-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181210182154.20357-1-geert+renesas@glider.be> References: <20181210182154.20357-1-geert+renesas@glider.be> Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 --- 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 | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index d8672336d4ff9b65..946cdb0c7250955f 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1272,6 +1272,8 @@ static void sci_dma_rx_complete(void *arg) struct dma_async_tx_descriptor *desc; unsigned long flags; int active, count = 0; + unsigned int i; + u16 scr; dev_dbg(port->dev, "%s(%d) active cookie %d\n", __func__, port->line, s->active_rx); @@ -1313,8 +1315,18 @@ 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); + dmaengine_terminate_async(chan); + for (i = 0; i < 2; i++) + s->cookie_rx[i] = -EINVAL; + s->active_rx = 0; s->chan_rx = NULL; - sci_start_rx(port); + /* Direct new serial port interrupts back to CPU */ + scr = serial_port_in(port, SCSCR); + if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) { + scr &= ~SCSCR_RDRQE; + enable_irq(s->irqs[SCIx_RXI_IRQ]); + } + serial_port_out(port, SCSCR, scr | SCSCR_RIE); spin_unlock_irqrestore(&port->lock, flags); }