From patchwork Fri Oct 30 01:52:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bhaumik Bhatt X-Patchwork-Id: 11868225 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 42CAD61C for ; Fri, 30 Oct 2020 01:52:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 120F520723 for ; Fri, 30 Oct 2020 01:52:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="Y9KOmIfx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726359AbgJ3BwY (ORCPT ); Thu, 29 Oct 2020 21:52:24 -0400 Received: from m42-4.mailgun.net ([69.72.42.4]:15865 "EHLO m42-4.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726329AbgJ3BwS (ORCPT ); Thu, 29 Oct 2020 21:52:18 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1604022737; h=References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=Du0L7znsZbpysoHB9CLpyUVXUEDUv0T27NVa+UG6pNg=; b=Y9KOmIfxXG0h9g6eweOFwvCQxuPSlCadeOGzVwfCjIqGEyzdv4l6+2+FYzgBdRJfmD8qn45E SygDzB1/P8HBrzz5mjNE5VbnjUz0vqDH3sSGSam5qCa8syOQiRq2f1lhiV6I3HYtg85OiY5R uH0NkJHZWvrtUaR9iISRHIMwGtE= X-Mailgun-Sending-Ip: 69.72.42.4 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-n07.prod.us-west-2.postgun.com with SMTP id 5f9b71d11df7f5f83c791876 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Fri, 30 Oct 2020 01:52:17 GMT Sender: bbhatt=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 48FB3C433FE; Fri, 30 Oct 2020 01:52:17 +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 EF0FEC433FE; Fri, 30 Oct 2020 01:52:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org EF0FEC433FE 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 v2 11/12] bus: mhi: core: Mark and maintain device states early on after power down Date: Thu, 29 Oct 2020 18:52:02 -0700 Message-Id: <1604022723-34578-12-git-send-email-bbhatt@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1604022723-34578-1-git-send-email-bbhatt@codeaurora.org> References: <1604022723-34578-1-git-send-email-bbhatt@codeaurora.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org mhi_power_down() does not ensure that the PM state is moved to an inaccessible state soon enough as the system can encounter scheduling delays till mhi_pm_disable_transition() gets called. Additionally, if an MHI controller decides that the device is now inaccessible and issues a power down, the register inaccessible state is not maintained by moving from MHI_PM_LD_ERR_FATAL_DETECT to MHI_PM_SHUTDOWN_PROCESS. This can result in bus errors if a client driver attempted to read registers when powering down. Close these gaps and avoid any race conditions to prevent such activity. Signed-off-by: Bhaumik Bhatt --- drivers/bus/mhi/core/pm.c | 77 ++++++++++++++++++++--------------------------- 1 file changed, 33 insertions(+), 44 deletions(-) diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c index 347ae7d..ffbf6f5 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 }, }; @@ -445,10 +446,9 @@ static int mhi_pm_mission_mode_transition(struct mhi_controller *mhi_cntrl) } /* Handle shutdown transitions */ -static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl, - enum mhi_pm_state transition_state) +static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl) { - enum mhi_pm_state cur_state, prev_state; + enum mhi_pm_state cur_state; struct mhi_event *mhi_event; struct mhi_cmd_ctxt *cmd_ctxt; struct mhi_cmd *mhi_cmd; @@ -456,33 +456,13 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl, struct device *dev = &mhi_cntrl->mhi_dev->dev; int ret, i; - dev_dbg(dev, "Transitioning from PM state: %s to: %s\n", - to_mhi_pm_state_str(mhi_cntrl->pm_state), - to_mhi_pm_state_str(transition_state)); + dev_dbg(dev, "Processing disable transition with PM state: %s\n", + to_mhi_pm_state_str(mhi_cntrl->pm_state)); mutex_lock(&mhi_cntrl->pm_mutex); - write_lock_irq(&mhi_cntrl->pm_lock); - prev_state = mhi_cntrl->pm_state; - cur_state = mhi_tryset_pm_state(mhi_cntrl, transition_state); - if (cur_state == transition_state) { - mhi_cntrl->ee = MHI_EE_DISABLE_TRANSITION; - mhi_cntrl->dev_state = MHI_STATE_RESET; - } - write_unlock_irq(&mhi_cntrl->pm_lock); - - /* Wake up threads waiting for state transition */ - wake_up_all(&mhi_cntrl->state_event); - - if (cur_state != transition_state) { - dev_err(dev, "Failed to transition to state: %s from: %s\n", - to_mhi_pm_state_str(transition_state), - to_mhi_pm_state_str(cur_state)); - mutex_unlock(&mhi_cntrl->pm_mutex); - return; - } /* Trigger MHI RESET so that the device will not access host memory */ - if (MHI_REG_ACCESS_VALID(prev_state)) { + if (!MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state)) { u32 in_reset = -1; unsigned long timeout = msecs_to_jiffies(mhi_cntrl->timeout_ms); @@ -785,8 +765,7 @@ void mhi_pm_st_worker(struct work_struct *work) mhi_pm_sys_error_transition(mhi_cntrl); break; case DEV_ST_TRANSITION_DISABLE: - mhi_pm_disable_transition - (mhi_cntrl, MHI_PM_SHUTDOWN_PROCESS); + mhi_pm_disable_transition(mhi_cntrl); break; default: break; @@ -1153,23 +1132,33 @@ 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 mhi_pm_state cur_state, transition_state; struct device *dev = &mhi_cntrl->mhi_dev->dev; /* If it's not a graceful shutdown, force MHI to linkdown state */ - if (!graceful) { - mutex_lock(&mhi_cntrl->pm_mutex); - write_lock_irq(&mhi_cntrl->pm_lock); - cur_state = mhi_tryset_pm_state(mhi_cntrl, - MHI_PM_LD_ERR_FATAL_DETECT); - write_unlock_irq(&mhi_cntrl->pm_lock); - mutex_unlock(&mhi_cntrl->pm_mutex); - if (cur_state != MHI_PM_LD_ERR_FATAL_DETECT) - 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)); + transition_state = (graceful) ? MHI_PM_SHUTDOWN_PROCESS : + MHI_PM_LD_ERR_FATAL_DETECT; + + mutex_lock(&mhi_cntrl->pm_mutex); + write_lock_irq(&mhi_cntrl->pm_lock); + cur_state = mhi_tryset_pm_state(mhi_cntrl, transition_state); + if (cur_state != transition_state) { + dev_err(dev, "Failed to move to state: %s from: %s\n", + to_mhi_pm_state_str(transition_state), + to_mhi_pm_state_str(mhi_cntrl->pm_state)); + /* Force link down or error fatal detected state */ + mhi_cntrl->pm_state = MHI_PM_LD_ERR_FATAL_DETECT; } + /* mark device inactive to avoid any further host processing */ + mhi_cntrl->ee = MHI_EE_DISABLE_TRANSITION; + mhi_cntrl->dev_state = MHI_STATE_RESET; + + wake_up_all(&mhi_cntrl->state_event); + + write_unlock_irq(&mhi_cntrl->pm_lock); + mutex_unlock(&mhi_cntrl->pm_mutex); + mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE); /* Wait for shutdown to complete */