From patchwork Tue Sep 1 15:02:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 256356 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=-11.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS, 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 B5FD1C433E6 for ; Tue, 1 Sep 2020 15:03:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4035A206FA for ; Tue, 1 Sep 2020 15:03:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b="Xyf7yP3/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726895AbgIAPDA (ORCPT ); Tue, 1 Sep 2020 11:03:00 -0400 Received: from www.zeus03.de ([194.117.254.33]:44196 "EHLO mail.zeus03.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728418AbgIAPC5 (ORCPT ); Tue, 1 Sep 2020 11:02:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple; d=sang-engineering.com; h= from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; s=k1; bh=DL6NFyOKpUaIvPMuHk7soZwzuQh V7fucyf3pAdXHfs0=; b=Xyf7yP3/xTJz3RAeTs9v1L5q+MoqqcNFmzFlm10+Qfo 4KlSaRH/0lhfnswSv4qQA9q69wRL3lTV/eal4dizDOSub235UI538SwK4TA0YZbd jmzKp1xGADAdudtz5+3Ktdw8ASyFI9hCc63VYOLf67vsCagbbFQ74xr7+hd5Zqn0 = Received: (qmail 2554147 invoked from network); 1 Sep 2020 17:02:55 +0200 Received: by mail.zeus03.de with ESMTPSA (TLS_AES_256_GCM_SHA384 encrypted, authenticated); 1 Sep 2020 17:02:55 +0200 X-UD-Smtp-Session: l3s3148p1@PPNZ0EGuWowgAwDPXxBIAL7SzoTwUEK2 From: Wolfram Sang To: linux-mmc@vger.kernel.org Cc: linux-renesas-soc@vger.kernel.org, Yoshihiro Shimoda , Wolfram Sang Subject: [PATCH v2 0/4] renesas_sdhi: fix hang when SCC loses its clock Date: Tue, 1 Sep 2020 17:02:46 +0200 Message-Id: <20200901150250.26236-1-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org This again took a while since v1 because the issue was so hard to trigger. But I finally found a way to inject the flaw, so this series could be tested and it fixes the issue. Changes since v1: * introduce a new flag to MMC core indicating any kind of tuning not only retune * use the new flag to keep SCC flag active * new patch 4, minor cleanup to MMC core A branch including the DEBUG patch can be found here: git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git renesas/sdhi/new_manual_calib-for-5.10 If you revert patch 3, you should have the SCC hang during boot again. For the record, let me copy some findings I mentioned in another thread: === Interesting news: The hang comes from a code path I would have not expected. It is not because of accessing an SCC register, it is this line from renesas_sdhi_set_clock() which causes the issue: 186 sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, clk & CLK_CTL_DIV_MASK); I mean I can guess that the clock setting has something to do with the SCC, but I can't see the direct connection with the documentation I have. === Tested on R-Car H3 ES2.0 and M3-N and patches based on mmc/next. Another hope this is gone for good now... Kind regards, Wolfram Wolfram Sang (4): mmc: core: when downgrading HS400, callback into drivers earlier mmc: core: add a 'doing_init_tune' flag and a 'mmc_doing_tune' helper mmc: renesas_sdhi: keep SCC clock active when tuning mmc: core: simplify an expression drivers/mmc/core/mmc.c | 16 ++++++++++------ drivers/mmc/host/renesas_sdhi_core.c | 8 ++++++-- include/linux/mmc/host.h | 6 ++++++ 3 files changed, 22 insertions(+), 8 deletions(-)