From patchwork Tue Feb 16 20:52:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeffrey Hugo X-Patchwork-Id: 12090601 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=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 8E7B3C433E0 for ; Tue, 16 Feb 2021 20:53:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2A17364EAD for ; Tue, 16 Feb 2021 20:53:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230234AbhBPUx1 (ORCPT ); Tue, 16 Feb 2021 15:53:27 -0500 Received: from m42-2.mailgun.net ([69.72.42.2]:21237 "EHLO m42-2.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230222AbhBPUx0 (ORCPT ); Tue, 16 Feb 2021 15:53:26 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1613508785; h=Content-Transfer-Encoding: MIME-Version: Message-Id: Date: Subject: Cc: To: From: Sender; bh=DJ/cCF5+Vw35+SimUiMhAKV4yrK2QxIJTWhxd5v/t40=; b=Ep28obXmFoOWGBRwtEOuwSn8SHNZ0yvkH2TxHe1FFWhmJFKWIl5OuLhPOGngtDFZXShbO5qJ w5jWkQs9v4Gp//KBkw3xeSoBsKGcbw6uJ9SyZ9RpwOYtegjHniJ2VLNVD0cRfCd2XLt5Z//y 8bD8ofM4DQII+4XRJxE7TY0uQP8= X-Mailgun-Sending-Ip: 69.72.42.2 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-east-1.postgun.com with SMTP id 602c309206bddda9dfe82bf5 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Tue, 16 Feb 2021 20:52:34 GMT Sender: jhugo=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 5EAE8C43462; Tue, 16 Feb 2021 20:52:33 +0000 (UTC) Received: from jhugo-lnx.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: jhugo) by smtp.codeaurora.org (Postfix) with ESMTPSA id 413C8C433CA; Tue, 16 Feb 2021 20:52:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 413C8C433CA 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=jhugo@codeaurora.org From: Jeffrey Hugo To: manivannan.sadhasivam@linaro.org, hemantk@codeaurora.org Cc: bbhatt@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Jeffrey Hugo Subject: [PATCH] mhi_bus: core: Wait for ready state after reset Date: Tue, 16 Feb 2021 13:52:25 -0700 Message-Id: <1613508745-32324-1-git-send-email-jhugo@codeaurora.org> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org After the device has signaled the end of reset by clearing the reset bit, it will automatically reinit MHI and the internal device structures. Once That is done, the device will signal it has entered the ready state. Signaling the ready state involves sending an interrupt (MSI) to the host which might cause IOMMU faults if it occurs at the wrong time. If the controller is being powered down, and possibly removed, then the reset flow would only wait for the end of reset. At which point, the host and device would start a race. The host may complete its reset work, and remove the interrupt handler, which would cause the interrupt to be disabled in the IOMMU. If that occurs before the device signals the ready state, then the IOMMU will fault since it blocked an interrupt. While harmless, the fault would appear like a serious issue has occurred so let's silence it by making sure the device hits the ready state before the host completes its reset processing. Signed-off-by: Jeffrey Hugo Reported-by: kernel test robot Reported-by: kernel test robot Reported-by: Dan Carpenter --- drivers/bus/mhi/core/pm.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c index ef8fb4a..dc69074 100644 --- a/drivers/bus/mhi/core/pm.c +++ b/drivers/bus/mhi/core/pm.c @@ -463,7 +463,7 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl) /* Trigger MHI RESET so that the device will not access host memory */ if (!MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state)) { - u32 in_reset = -1; + u32 in_reset = -1, ready = 0; unsigned long timeout = msecs_to_jiffies(mhi_cntrl->timeout_ms); dev_dbg(dev, "Triggering MHI Reset in device\n"); @@ -486,6 +486,25 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl) * hence re-program it */ mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0); + + if (!MHI_IN_PBL(mhi_get_exec_env(mhi_cntrl))) { + /* wait for ready to be set */ + ret = wait_event_timeout(mhi_cntrl->state_event, + mhi_read_reg_field(mhi_cntrl, + mhi_cntrl->regs, + MHISTATUS, + MHISTATUS_READY_MASK, + MHISTATUS_READY_SHIFT, + &ready) + || ready, timeout); + if ((!ret || !ready) && + cur_state == MHI_PM_SYS_ERR_PROCESS) { + dev_err(dev, + "Device failed to enter READY state\n"); + mutex_unlock(&mhi_cntrl->pm_mutex); + return; + } + } } dev_dbg(dev,