From patchwork Sat Sep 19 02:02:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bhaumik Bhatt X-Patchwork-Id: 11786547 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C0218112E for ; Sat, 19 Sep 2020 02:03:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A52E521707 for ; Sat, 19 Sep 2020 02:03:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="qLApG/Vh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726421AbgISCDD (ORCPT ); Fri, 18 Sep 2020 22:03:03 -0400 Received: from so254-54.mailgun.net ([198.61.254.54]:45635 "EHLO so254-54.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726376AbgISCCy (ORCPT ); Fri, 18 Sep 2020 22:02:54 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1600480973; h=References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=ZdfA1vgYrXj47yJw43/hc550AS1dLK/hDR1YnTZowuI=; b=qLApG/VhcUkj3Yyz1tNspcWtEk5ynlTIbnc4L3HuGduM8U+cpWcKVRqB5y9Lz9u+KU7EUVu8 FdzWHDFyBlFHq+pi/degDebeq59zv7l0TLHz5n2CV5vHCJ8/84T1hMN3aluPvifBO/REL6Am 2rq8r0Av/jOrHqSCDkybbKbz7Jo= X-Mailgun-Sending-Ip: 198.61.254.54 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-east-1.postgun.com with SMTP id 5f6566c86ace44cacceed691 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Sat, 19 Sep 2020 02:02:48 GMT Sender: bbhatt=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 968E5C433CB; Sat, 19 Sep 2020 02:02:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-caf-mail-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=ALL_TRUSTED,BAYES_00,SPF_FAIL, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from malabar-linux.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: bbhatt) by smtp.codeaurora.org (Postfix) with ESMTPSA id 6AF15C433F1; Sat, 19 Sep 2020 02:02:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 6AF15C433F1 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=fail smtp.mailfrom=bbhatt@codeaurora.org From: Bhaumik Bhatt To: manivannan.sadhasivam@linaro.org Cc: linux-arm-msm@vger.kernel.org, hemantk@codeaurora.org, jhugo@codeaurora.org, linux-kernel@vger.kernel.org, Bhaumik Bhatt Subject: [PATCH v1 06/10] bus: mhi: core: Improve shutdown handling after link down detection Date: Fri, 18 Sep 2020 19:02:31 -0700 Message-Id: <1600480955-16827-7-git-send-email-bbhatt@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1600480955-16827-1-git-send-email-bbhatt@codeaurora.org> References: <1600480955-16827-1-git-send-email-bbhatt@codeaurora.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org If MHI were to attempt a device shutdown following an assumption that the device is inaccessible, the host currently moves to a state where device register accesses are allowed when they should not be. This would end up allowing accesses to the device register space when the link is inaccessible and can result in bus errors observed on the host. Improve shutdown handling to prevent these outcomes and do not move the MHI PM state to a register accessible state after device is assumed to be inaccessible. Signed-off-by: Bhaumik Bhatt --- drivers/bus/mhi/core/init.c | 1 + drivers/bus/mhi/core/internal.h | 1 + drivers/bus/mhi/core/pm.c | 18 +++++++++++++----- 3 files changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c index 9ae4c19..fa33dde 100644 --- a/drivers/bus/mhi/core/init.c +++ b/drivers/bus/mhi/core/init.c @@ -37,6 +37,7 @@ const char * const dev_state_tran_str[DEV_ST_TRANSITION_MAX] = { [DEV_ST_TRANSITION_MISSION_MODE] = "MISSION_MODE", [DEV_ST_TRANSITION_SYS_ERR] = "SYS_ERR", [DEV_ST_TRANSITION_DISABLE] = "DISABLE", + [DEV_ST_TRANSITION_FATAL] = "FATAL SHUTDOWN", }; const char * const mhi_state_str[MHI_STATE_MAX] = { diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h index 7989269..f3b9e5a 100644 --- a/drivers/bus/mhi/core/internal.h +++ b/drivers/bus/mhi/core/internal.h @@ -388,6 +388,7 @@ enum dev_st_transition { DEV_ST_TRANSITION_MISSION_MODE, DEV_ST_TRANSITION_SYS_ERR, DEV_ST_TRANSITION_DISABLE, + DEV_ST_TRANSITION_FATAL, DEV_ST_TRANSITION_MAX, }; diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c index 3462d82..bce1f62 100644 --- a/drivers/bus/mhi/core/pm.c +++ b/drivers/bus/mhi/core/pm.c @@ -37,9 +37,10 @@ * M0 -> FW_DL_ERR * M0 -> M3_ENTER -> M3 -> M3_EXIT --> M0 * L1: SYS_ERR_DETECT -> SYS_ERR_PROCESS --> POR - * L2: SHUTDOWN_PROCESS -> DISABLE + * L2: SHUTDOWN_PROCESS -> LD_ERR_FATAL_DETECT + * SHUTDOWN_PROCESS -> DISABLE * L3: LD_ERR_FATAL_DETECT <--> LD_ERR_FATAL_DETECT - * LD_ERR_FATAL_DETECT -> SHUTDOWN_PROCESS + * LD_ERR_FATAL_DETECT -> DISABLE */ static struct mhi_pm_transitions const dev_state_transitions[] = { /* L0 States */ @@ -72,7 +73,7 @@ static struct mhi_pm_transitions const dev_state_transitions[] = { { MHI_PM_M3, MHI_PM_M3_EXIT | MHI_PM_SYS_ERR_DETECT | - MHI_PM_SHUTDOWN_PROCESS | MHI_PM_LD_ERR_FATAL_DETECT + MHI_PM_LD_ERR_FATAL_DETECT }, { MHI_PM_M3_EXIT, @@ -103,7 +104,7 @@ static struct mhi_pm_transitions const dev_state_transitions[] = { /* L3 States */ { MHI_PM_LD_ERR_FATAL_DETECT, - MHI_PM_LD_ERR_FATAL_DETECT | MHI_PM_SHUTDOWN_PROCESS + MHI_PM_LD_ERR_FATAL_DETECT | MHI_PM_DISABLE }, }; @@ -670,6 +671,10 @@ void mhi_pm_st_worker(struct work_struct *work) mhi_pm_disable_transition (mhi_cntrl, MHI_PM_SHUTDOWN_PROCESS); break; + case DEV_ST_TRANSITION_FATAL: + mhi_pm_disable_transition + (mhi_cntrl, MHI_PM_LD_ERR_FATAL_DETECT); + break; default: break; } @@ -1039,6 +1044,7 @@ EXPORT_SYMBOL_GPL(mhi_async_power_up); void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful) { enum mhi_pm_state cur_state; + enum dev_st_transition next_state = DEV_ST_TRANSITION_DISABLE; struct device *dev = &mhi_cntrl->mhi_dev->dev; /* If it's not a graceful shutdown, force MHI to linkdown state */ @@ -1053,9 +1059,11 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful) dev_dbg(dev, "Failed to move to state: %s from: %s\n", to_mhi_pm_state_str(MHI_PM_LD_ERR_FATAL_DETECT), to_mhi_pm_state_str(mhi_cntrl->pm_state)); + else + next_state = DEV_ST_TRANSITION_FATAL; } - mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE); + mhi_queue_state_transition(mhi_cntrl, next_state); /* Wait for shutdown to complete */ flush_work(&mhi_cntrl->st_worker);