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[23.128.96.18]) by mx.google.com with ESMTP id d27si564967ejt.291.2020.12.02.01.46.42; Wed, 02 Dec 2020 01:46:42 -0800 (PST) Received-SPF: pass (google.com: domain of linux-arm-msm-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b="Yu3nOBg/"; spf=pass (google.com: domain of linux-arm-msm-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-arm-msm-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388349AbgLBJpG (ORCPT + 15 others); Wed, 2 Dec 2020 04:45:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54904 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388556AbgLBJod (ORCPT ); Wed, 2 Dec 2020 04:44:33 -0500 Received: from mail-pg1-x542.google.com (mail-pg1-x542.google.com [IPv6:2607:f8b0:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DDA06C061A4B for ; Wed, 2 Dec 2020 01:43:57 -0800 (PST) Received: by mail-pg1-x542.google.com with SMTP id n7so302145pgg.2 for ; Wed, 02 Dec 2020 01:43:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=UqJtPPbam5F4e6lWYSMgvhm5ifJn4YWUg9vIO4IndOc=; b=Yu3nOBg/WmUy21MfNUE/dGvV8kG5uWRcbNvXGAxcCcCu0pgrx1eJ9ovJn2xuSn0NVF r6n5dJkVVTCxTu/VJrQ4wxFCuQjLAxoMDzSDlLgDuG8UJsG4t+NRdU65qNh49ZQlvBop IJpVIiZnGranLAnFleZNWCIhEkwcgUfIM3KcNlwPIB+jbSlaa0NVFB0+3/QL5Yff/8Fj ARKeiSFLGxO4LdXldbbGa1kP48gvVW0gdR8mB5ykaVzMIIPwJZWYIuEen8zDA1qr3rji k/lfQdn0MBHMjEhGQv0eLwtWSXaaJo95HnL9tzeGsmqhXUrRMEvGlKlcqJFn8NXtCcgz 89lg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=UqJtPPbam5F4e6lWYSMgvhm5ifJn4YWUg9vIO4IndOc=; b=m5mPIJOHJjjzvkbj1ajE+ZuJJlng2SLSd5UYMnoPwlhb7DcylI/U1yNUXzfEIU6zK1 Ju8kNpqeVj+DZgVFlcyPXMsNBVl6dLrBI5hTlXuZfDfcbpvzeek/2dexPkGECkdHj88u Shv9i8GvmwJDv7eitcaFMUrUvgfZPgCzerPyt22rczTFatmG/EDNUW/tzB38t+K/MP6H 6SRdUf0IGMX9b02+pFYQjxUoTfxhKRxA5KBhyQq1skoSMiAgEKAPOcTpS5jkU6OtslP8 kZmdi87iyjywcfwrwpGAMM8zjneZTxPppWybYWkkVIrv/SeyHx38oV1AG/poNS0mKiTd FSXA== X-Gm-Message-State: AOAM532CDLOra6reCA5ty0tXxCL0i/iH6FJ+dEGWszR8KNDwwGPvE2Ha KUs61oYb584wR1n3HecWEtmE X-Received: by 2002:a63:368e:: with SMTP id d136mr1885181pga.239.1606902237328; Wed, 02 Dec 2020 01:43:57 -0800 (PST) Received: from localhost.localdomain ([103.59.133.81]) by smtp.gmail.com with ESMTPSA id bg8sm1393990pjb.52.2020.12.02.01.43.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Dec 2020 01:43:56 -0800 (PST) From: Manivannan Sadhasivam To: gregkh@linuxfoundation.org Cc: hemantk@codeaurora.org, bbhatt@codeaurora.org, linux-arm-msm@vger.kernel.org, jhugo@codeaurora.org, linux-kernel@vger.kernel.org, loic.poulain@linaro.org, Manivannan Sadhasivam Subject: [PATCH 23/29] bus: mhi: core: Mark and maintain device states early on after power down Date: Wed, 2 Dec 2020 15:11:53 +0530 Message-Id: <20201202094159.107075-24-manivannan.sadhasivam@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201202094159.107075-1-manivannan.sadhasivam@linaro.org> References: <20201202094159.107075-1-manivannan.sadhasivam@linaro.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org From: Bhaumik Bhatt 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 Signed-off-by: Manivannan Sadhasivam --- drivers/bus/mhi/core/pm.c | 77 +++++++++++++++++---------------------- 1 file changed, 33 insertions(+), 44 deletions(-) -- 2.25.1 diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c index 347ae7dd6cf8..ffbf6f539510 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 */