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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 BB668C433B4 for ; Mon, 19 Apr 2021 20:52:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 87BDF6101C for ; Mon, 19 Apr 2021 20:52:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243559AbhDSUwp (ORCPT ); Mon, 19 Apr 2021 16:52:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:59582 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243040AbhDSUuT (ORCPT ); Mon, 19 Apr 2021 16:50:19 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3FF7A613F2; Mon, 19 Apr 2021 20:46:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1618865177; bh=EroOQ0Q5+LWxmqIPkjSFXpRaSG7tnHFi6dfe9tXtcL8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bkl8wt9ZB6IdQc7849UQ3LGE/XyLH+R48R9WWP9XiPlwMi466Ody1QiPor0ztv3vQ JlTZ/huqbckCsnYOnN0gBDJ9ku3Ut9H16NfFQxUUtJQ8hCUr98esDSKd+u9TKetl0c WgwmrdyX9k7SKh4gSzM1ifbgGrla0o+MiC7vd2wArwmmTV6CZsowdMq+nyjyOGUzxR 2T71qfYxLB5H2lvgjvYn6WyA7qZVJBjaxTslvGtZ269frzOM1ez9V8QcwIuaoCBM4r iMO5E3WkiaxRhhxcSU2hiPChmnnR3obGhlltqm45mRmlWUIMpVQ22SSbrf7fLp1Lnh 6RNLcHamjJzFw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: =?UTF-8?q?Marek=20Beh=C3=BAn?= , Gregory CLEMENT , Samuel Holland , Wolfram Sang , Sasha Levin , linux-i2c@vger.kernel.org Subject: [PATCH AUTOSEL 4.4 5/7] i2c: mv64xxx: Fix random system lock caused by runtime PM Date: Mon, 19 Apr 2021 16:46:06 -0400 Message-Id: <20210419204608.7191-5-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210419204608.7191-1-sashal@kernel.org> References: <20210419204608.7191-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marek Behún [ Upstream commit 39930213e7779b9c4257499972b8afb8858f1a2d ] I noticed a weird bug with this driver on Marvell CN9130 Customer Reference Board. Sometime after boot, the system locks with the following message: [104.071363] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 The system does not respond afterwards, only warns about RCU stalls. This first appeared with commit e5c02cf54154 ("i2c: mv64xxx: Add runtime PM support"). With further experimentation I discovered that adding a delay into mv64xxx_i2c_hw_init() fixes this issue. This function is called before every xfer, due to how runtime PM works in this driver. It seems that in order to work correctly, a delay is needed after the bus is reset in this function. Since there already is a known erratum with this controller needing a delay, I assume that this is just another place this needs to be applied. Therefore I apply the delay only if errata_delay is true. Signed-off-by: Marek Behún Acked-by: Gregory CLEMENT Reviewed-by: Samuel Holland Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-mv64xxx.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c index 332d32c53c41..73324f047932 100644 --- a/drivers/i2c/busses/i2c-mv64xxx.c +++ b/drivers/i2c/busses/i2c-mv64xxx.c @@ -219,6 +219,10 @@ mv64xxx_i2c_hw_init(struct mv64xxx_i2c_data *drv_data) writel(0, drv_data->reg_base + drv_data->reg_offsets.ext_addr); writel(MV64XXX_I2C_REG_CONTROL_TWSIEN | MV64XXX_I2C_REG_CONTROL_STOP, drv_data->reg_base + drv_data->reg_offsets.control); + + if (drv_data->errata_delay) + udelay(5); + drv_data->state = MV64XXX_I2C_STATE_IDLE; } -- 2.30.2