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=-8.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,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 03708C43612 for ; Mon, 7 Jan 2019 16:23:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D33BB2173C for ; Mon, 7 Jan 2019 16:23:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729761AbfAGQX0 (ORCPT ); Mon, 7 Jan 2019 11:23:26 -0500 Received: from albert.telenet-ops.be ([195.130.137.90]:59592 "EHLO albert.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730196AbfAGQXZ (ORCPT ); Mon, 7 Jan 2019 11:23:25 -0500 Received: from ramsan ([84.194.111.163]) by albert.telenet-ops.be with bizsmtp id MUPM1z00S3XaVaC06UPM90; 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-0008Fv-Dd; 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-00043J-Bv; 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 0/4] serial: sh-sci: Fix fallback to PIO on DMA failure Date: Mon, 7 Jan 2019 17:23:16 +0100 Message-Id: <20190107162320.15530-1-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org Hi Greg, Jiri, When submitting a DMA request fails, the sh-sci driver is supposed to fall back to PIO. However, this never really worked due to various reasons (sh-sci driver issues and dmaengine framework limitations). There are three places where DMA submission can fail, and the driver should fall back to PIO: 1. sci_dma_rx_complete(), 2. sci_submit_rx(), 3. work_fn_tx(). This patch series fixes fallback to PIO in case 1, which is the only one that does not work yet in v5.0-rc1. Changes compared to v4: - Drop patches to fix case 2, whch have been applied in v5.0-rc1, - Add patches to extract common helpers and make naming more consistent, - Call new helpers sci_dma_rx_chan_invalidate() and sci_dma_rx_reenable_irq() instead of open-coding. Changes compared to v3: - Let sci_submit_rx() return -EAGAIN instead of -1 on failure, - Check for negative error in sci_submit_rx() caller. Changes compared to v2: - Add missing definition of "u16 scr" to sci_dma_rx_complete(), - Move label handle_pio inside #ifdef to kill defined but not used compiler warning when CONFIG_SERIAL_SH_SCI_DMA=n, - Move call to dmaengine_terminate_async() in sci_dma_rx_complete() inside the spinlock, for symmetry with sci_submit_rx(), - Move the call sci_submit_rx() in sci_rx_interrupt() up, as it may fail, rendering the modification of scr unused, - Split in multiple patches, - Drop RFC status. Changes compared to v1: - Fix fallback in sci_dma_rx_complete(), - Fallback in the transmit path already works fine, - Widen audience, but keep RFC. This has been tested on r8a7791/koelsch, using SCIF1 on debug serial 1, and SCIFA3 on EXIO-B, by introducing random failures in DMA submission code. For testing, this series is also available in the topic/scif-pio-fallback-v5 branch of my renesas-drivers git repository at git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git. Thanks! Geert Uytterhoeven (4): serial: sh-sci: Extract sci_dma_rx_chan_invalidate() serial: sh-sci: Extract sci_dma_rx_reenable_irq() serial: sh-sci: Fix fallback to PIO in sci_dma_rx_complete() serial: sh-sci: Make RX/TX DMA function names consistent drivers/tty/serial/sh-sci.c | 71 ++++++++++++++++++++++--------------- 1 file changed, 43 insertions(+), 28 deletions(-) -- 2.17.1 Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds