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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE515C433EF for ; Fri, 26 Nov 2021 04:10:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240350AbhKZENd (ORCPT ); Thu, 25 Nov 2021 23:13:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41460 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241959AbhKZELd (ORCPT ); Thu, 25 Nov 2021 23:11:33 -0500 Received: from mail-pf1-x42e.google.com (mail-pf1-x42e.google.com [IPv6:2607:f8b0:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D4848C07E5C2 for ; Thu, 25 Nov 2021 19:01:50 -0800 (PST) Received: by mail-pf1-x42e.google.com with SMTP id o4so7485236pfp.13 for ; Thu, 25 Nov 2021 19:01:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=BynVQIeiNIivT05KJS287cNnQbooVUGhheNqcoVB4w4=; b=iIt14tMtJniwQbZaAxQ3Est4t3Ff2ts/f/MX1Z156JA5MWVxigWssvjYU5EZJe36v6 EfRA2YIb7gMLSJ9e8AUw2SkHewhVtX8Z9PuFsPqlvq119QeECz648sU5fJUEmeTIIFeR /hX6E5r/BI4+vcbNBJCBK60qwZOeAQz7zuLat9mjGDPJI4OYB8GoXr0enoVLuNXlJ8t4 5ZpuZiKngvPQKsj4jlEsxGggQ8oex/vT8zIPqw2YucrnSFoEhV93a521klxipWNBZjuG 1EHaioBjoG8MjVspsZokAmRuGgs4CRnS4WydA99kE72y8p8lwR3+wlH3gvl2lV111t8q UlTw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=BynVQIeiNIivT05KJS287cNnQbooVUGhheNqcoVB4w4=; b=GHuLryx/1TuLj3M7NlEI7thgqOwtMltKrqJVL+PJydf7UzuMfQ6Pw9iOAGCWOEMFEV MYYLXVk3Oc+39QMu1VAdPtutBYXXSMpkYPWI6M4GhsZGhHmcZ3jt5qyiMwfmLjZOFEK6 9JZEUzUzG5/RL7eFSKshFFBfKqtvFiA8PW+y/xuphWgAEiebdBuUarfMgdxf+NExkd/o GQKZ/Qpnpr3gJx9MEqaT++l7mUKoctiWeZ72zRosfB2HxZcvgo2p/96C4msA5BakongX dw/QBSc4UEBo5H2AjijBjhNYtPX3ysQ49cGRho2R9dCXifKYmbVUyeRl0ZD+LcHQ8+rf c1sw== X-Gm-Message-State: AOAM533WLiw9lb4YtSK/YC3usiBGmNZYPYyr9zmp7gnDr5AIBpv4Efg1 KXbsbGDfen/NDXyd7wgkVsAD X-Google-Smtp-Source: ABdhPJzAB/unmK4+Mb/MfAf42HoI7g6onRWKtvspjP/fglbRciESFe8VcxE1LBEMAY1C7pt3p6LBqA== X-Received: by 2002:a63:4745:: with SMTP id w5mr19143246pgk.320.1637895710318; Thu, 25 Nov 2021 19:01:50 -0800 (PST) Received: from thinkpad ([117.215.117.247]) by smtp.gmail.com with ESMTPSA id h186sm4731054pfg.59.2021.11.25.19.01.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Nov 2021 19:01:49 -0800 (PST) Date: Fri, 26 Nov 2021 08:31:44 +0530 From: Manivannan Sadhasivam To: mhi@lists.linux.dev, quic_jhugo@quicinc.com, hemantk@codeaurora.org, bbhatt@codeaurora.org Cc: aleksander@aleksander.es, loic.poulain@linaro.org, thomas.perrot@bootlin.com, linux-arm-msm@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v4] bus: mhi: Fix race while handling SYS_ERR at power up Message-ID: <20211126030144.GC5859@thinkpad> References: <20211124132221.44915-1-manivannan.sadhasivam@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211124132221.44915-1-manivannan.sadhasivam@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Wed, Nov 24, 2021 at 06:52:21PM +0530, Manivannan Sadhasivam wrote: > Some devices tend to trigger SYS_ERR interrupt while the host handling > SYS_ERR state of the device during power up. This creates a race > condition and causes a failure in booting up the device. > > The issue is seen on the Sierra Wireless EM9191 modem during SYS_ERR > handling in mhi_async_power_up(). Once the host detects that the device > is in SYS_ERR state, it issues MHI_RESET and waits for the device to > process the reset request. During this time, the device triggers SYS_ERR > interrupt to the host and host starts handling SYS_ERR execution. > > So by the time the device has completed reset, host starts SYS_ERR > handling. This causes the race condition and the modem fails to boot. > > Hence, register the IRQ handler only after handling the SYS_ERR check > to avoid getting spurious IRQs from the device. > > Cc: stable@vger.kernel.org > Fixes: e18d4e9fa79b ("bus: mhi: core: Handle syserr during power_up") > Reported-by: Aleksander Morgado > Signed-off-by: Manivannan Sadhasivam Hemant, Bhaumik, Jeff: Can you please do the review again? Thanks, Mani > --- > > Changes in v4: > > * Reverted the change that moved BHI_INTVEC as that was causing issue as > reported by Aleksander. > > Changes in v3: > > * Moved BHI_INTVEC setup after irq setup > * Used interval_us as the delay for the polling API > > Changes in v2: > > * Switched to "mhi_poll_reg_field" for detecting MHI reset in device. > > drivers/bus/mhi/core/pm.c | 33 +++++++++++---------------------- > 1 file changed, 11 insertions(+), 22 deletions(-) > > diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c > index fb99e3727155..21484a61bbed 100644 > --- a/drivers/bus/mhi/core/pm.c > +++ b/drivers/bus/mhi/core/pm.c > @@ -1038,7 +1038,7 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) > enum mhi_ee_type current_ee; > enum dev_st_transition next_state; > struct device *dev = &mhi_cntrl->mhi_dev->dev; > - u32 val; > + u32 interval_us = 25000; /* poll register field every 25 milliseconds */ > int ret; > > dev_info(dev, "Requested to power ON\n"); > @@ -1055,10 +1055,6 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) > mutex_lock(&mhi_cntrl->pm_mutex); > mhi_cntrl->pm_state = MHI_PM_DISABLE; > > - ret = mhi_init_irq_setup(mhi_cntrl); > - if (ret) > - goto error_setup_irq; > - > /* Setup BHI INTVEC */ > write_lock_irq(&mhi_cntrl->pm_lock); > mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0); > @@ -1072,7 +1068,7 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) > dev_err(dev, "%s is not a valid EE for power on\n", > TO_MHI_EXEC_STR(current_ee)); > ret = -EIO; > - goto error_async_power_up; > + goto error_setup_irq; > } > > state = mhi_get_mhi_state(mhi_cntrl); > @@ -1081,20 +1077,12 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) > > if (state == MHI_STATE_SYS_ERR) { > mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET); > - ret = wait_event_timeout(mhi_cntrl->state_event, > - MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state) || > - mhi_read_reg_field(mhi_cntrl, > - mhi_cntrl->regs, > - MHICTRL, > - MHICTRL_RESET_MASK, > - MHICTRL_RESET_SHIFT, > - &val) || > - !val, > - msecs_to_jiffies(mhi_cntrl->timeout_ms)); > - if (!ret) { > - ret = -EIO; > + ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHICTRL, > + MHICTRL_RESET_MASK, MHICTRL_RESET_SHIFT, 0, > + interval_us); > + if (ret) { > dev_info(dev, "Failed to reset MHI due to syserr state\n"); > - goto error_async_power_up; > + goto error_setup_irq; > } > > /* > @@ -1104,6 +1092,10 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) > mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0); > } > > + ret = mhi_init_irq_setup(mhi_cntrl); > + if (ret) > + goto error_setup_irq; > + > /* Transition to next state */ > next_state = MHI_IN_PBL(current_ee) ? > DEV_ST_TRANSITION_PBL : DEV_ST_TRANSITION_READY; > @@ -1116,9 +1108,6 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) > > return 0; > > -error_async_power_up: > - mhi_deinit_free_irq(mhi_cntrl); > - > error_setup_irq: > mhi_cntrl->pm_state = MHI_PM_DISABLE; > mutex_unlock(&mhi_cntrl->pm_mutex); > -- > 2.25.1 >