From patchwork Mon Nov 9 20:47:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bhaumik Bhatt X-Patchwork-Id: 11892467 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 2C0C76A2 for ; Mon, 9 Nov 2020 20:48:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 07CE2206E3 for ; Mon, 9 Nov 2020 20:48:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="CqjnySaZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730772AbgKIUsG (ORCPT ); Mon, 9 Nov 2020 15:48:06 -0500 Received: from z5.mailgun.us ([104.130.96.5]:56205 "EHLO z5.mailgun.us" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730849AbgKIUrs (ORCPT ); Mon, 9 Nov 2020 15:47:48 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1604954867; h=References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=qyO25VVqZ3w0qDAFTOsWopOhDvFzLffbe+DdT/MQSwY=; b=CqjnySaZ867OitbnDOkcVJlRuP/kaEZ0JagVOFbAI64OyX9oNG7Uu5/IMT5G9946MaNLTHNR lC23o42LqJ5N2Daa7n/zKkXrWCXiTQoiGK5/KwB1RldMMWC6DhmOvnTdZRioNCRO3Y3jfQlh bdg1RsZcm79NV0X0+Dqam1IvCbM= X-Mailgun-Sending-Ip: 104.130.96.5 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-n05.prod.us-east-1.postgun.com with SMTP id 5fa9aaf38723a97b70f160ad (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 09 Nov 2020 20:47:47 GMT Sender: bbhatt=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 53A38C43387; Mon, 9 Nov 2020 20:47:46 +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 1B0D9C43385; Mon, 9 Nov 2020 20:47:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 1B0D9C43385 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 v4 11/12] bus: mhi: core: Mark and maintain device states early on after power down Date: Mon, 9 Nov 2020 12:47:30 -0800 Message-Id: <1604954851-23396-12-git-send-email-bbhatt@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1604954851-23396-1-git-send-email-bbhatt@codeaurora.org> References: <1604954851-23396-1-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 Reviewed-by: Manivannan Sadhasivam --- 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 */