From patchwork Wed May 27 13:55:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lindgren X-Patchwork-Id: 211363 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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, 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 9AA1CC433DF for ; Wed, 27 May 2020 13:55:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74148207D8 for ; Wed, 27 May 2020 13:55:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389024AbgE0Nzu (ORCPT ); Wed, 27 May 2020 09:55:50 -0400 Received: from muru.com ([72.249.23.125]:55818 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388991AbgE0Nzu (ORCPT ); Wed, 27 May 2020 09:55:50 -0400 Received: from hillo.muru.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTP id E5A1780DB; Wed, 27 May 2020 13:56:39 +0000 (UTC) From: Tony Lindgren To: linux-omap@vger.kernel.org Cc: "Andrew F . Davis" , Dave Gerlach , Faiz Abbas , Greg Kroah-Hartman , Keerthy , Nishanth Menon , Peter Ujfalusi , Roger Quadros , Suman Anna , Tero Kristo , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH] bus: ti-sysc: Flush posted write on enable and disable Date: Wed, 27 May 2020 06:55:39 -0700 Message-Id: <20200527135539.49059-1-tony@atomide.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org Looks like we're missing flush of posted write after module enable and disable. I've seen occasional errors accessing various modules, and it is suspected that the lack of posted writes can also cause random reboots. The errors we can see are similar to the one below from spi for example: 44000000.ocp:L3 Custom Error: MASTER MPU TARGET L4CFG (Read): Data Access in User mode during Functional access ... mcspi_wait_for_reg_bit omap2_mcspi_transfer_one spi_transfer_one_message ... We also want to also flush posted write for disable. The clkctrl clock disable happens after module disable, and we don't want to have the module potentially stay active while we're trying to disable the clock. Fixes: d59b60564cbf ("bus: ti-sysc: Add generic enable/disable functions") Signed-off-by: Tony Lindgren --- drivers/bus/ti-sysc.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c --- a/drivers/bus/ti-sysc.c +++ b/drivers/bus/ti-sysc.c @@ -991,6 +991,9 @@ static int sysc_enable_module(struct device *dev) sysc_write_sysconfig(ddata, reg); } + /* Flush posted write */ + sysc_read(ddata, ddata->offsets[SYSC_SYSCONFIG]); + if (ddata->module_enable_quirk) ddata->module_enable_quirk(ddata); @@ -1071,6 +1074,9 @@ static int sysc_disable_module(struct device *dev) reg |= 1 << regbits->autoidle_shift; sysc_write_sysconfig(ddata, reg); + /* Flush posted write */ + sysc_read(ddata, ddata->offsets[SYSC_SYSCONFIG]); + return 0; }