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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 A300FC2BB55 for ; Tue, 7 Apr 2020 15:11:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E81420692 for ; Tue, 7 Apr 2020 15:11:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="K71GmFq2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729198AbgDGPLi (ORCPT ); Tue, 7 Apr 2020 11:11:38 -0400 Received: from mail26.static.mailgun.info ([104.130.122.26]:64224 "EHLO mail26.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728992AbgDGPLi (ORCPT ); Tue, 7 Apr 2020 11:11:38 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1586272297; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=lo5LeBpU88t4FSGojL6rVJm8xZPofQsMUW6HaXesTPQ=; b=K71GmFq22Xz+EfxrOS8J8o27akemOxJ8YhZJT6w9hSPHNkR62v74RMtU7NFK6u1N2fYOcWhy xYU3OSeM7pgOCF4rLi4psFc2TOhcSPOUqIPMCqd0gyTfMDLKMiV5Jegl90wPicS8ZYlybGDq VkpwaxD0ujMJHRLpW2dDRuJY+Wk= X-Mailgun-Sending-Ip: 104.130.122.26 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by mxa.mailgun.org with ESMTP id 5e8c9828.7f7115275ae8-smtp-out-n02; Tue, 07 Apr 2020 15:11:36 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 53711C433D2; Tue, 7 Apr 2020 15:11:35 +0000 (UTC) Received: from [10.226.58.28] (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: jhugo) by smtp.codeaurora.org (Postfix) with ESMTPSA id 94892C433F2; Tue, 7 Apr 2020 15:11:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 94892C433F2 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=jhugo@codeaurora.org Subject: Re: [PATCH 1/3] bus: mhi: core: Handle syserr during power_up To: Manivannan Sadhasivam Cc: hemantk@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org References: <1586207077-22361-1-git-send-email-jhugo@codeaurora.org> <1586207077-22361-2-git-send-email-jhugo@codeaurora.org> <20200407062641.GC2442@Mani-XPS-13-9360> From: Jeffrey Hugo Message-ID: Date: Tue, 7 Apr 2020 09:11:33 -0600 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: <20200407062641.GC2442@Mani-XPS-13-9360> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/7/2020 12:26 AM, Manivannan Sadhasivam wrote: > On Mon, Apr 06, 2020 at 03:04:35PM -0600, Jeffrey Hugo wrote: >> The MHI device may be in the syserr state when we attempt to init it in >> power_up(). Since we have no local state, the handling is simple - >> reset the device and wait for it to transition out of the reset state. >> >> Signed-off-by: Jeffrey Hugo >> --- >> drivers/bus/mhi/core/pm.c | 20 ++++++++++++++++++++ >> 1 file changed, 20 insertions(+) >> >> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c >> index 52690cb..cd6ba23 100644 >> --- a/drivers/bus/mhi/core/pm.c >> +++ b/drivers/bus/mhi/core/pm.c >> @@ -9,6 +9,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -760,6 +761,7 @@ static void mhi_deassert_dev_wake(struct mhi_controller *mhi_cntrl, >> >> int mhi_async_power_up(struct mhi_controller *mhi_cntrl) >> { >> + enum mhi_state state; >> enum mhi_ee_type current_ee; >> enum dev_st_transition next_state; >> struct device *dev = &mhi_cntrl->mhi_dev->dev; >> @@ -829,6 +831,24 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) >> goto error_bhi_offset; >> } >> >> + state = mhi_get_mhi_state(mhi_cntrl); >> + if (state == MHI_STATE_SYS_ERR) { >> + mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET); >> + ret = readl_poll_timeout(mhi_cntrl->regs + MHICTRL, val, >> + !(val & MHICTRL_RESET_MASK), 1000, > > Hmm. Do we really need a max 1ms delay between each read? I'd prefer to have > 100ns to reduce the wait time. I assume you mean 100us since that's the units of the parameter, and usleep_range is the actual delay mechanism. Please correct me if that is a bad assumption. I chose 1ms to try to avoid flooding the bus, since on one system we care about, the round trip time was observed to be ~1ms. However, that is fairly arbitrary, so a factor of 10 reduction don't seem like a significant issue. > >> + mhi_cntrl->timeout_ms * 1000); >> + if (ret) { >> + dev_info(dev, "Failed to reset syserr\n"); > > dev_info(dev, "Failed to reset MHI due to syserr state\n"); ? > Ah yes, that is clearer. Thanks -- Jeffrey Hugo Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.