From mboxrd@z Thu Jan 1 00:00:00 1970 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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 7CED1C43460 for ; Fri, 21 May 2021 12:29:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5FE0C613EA for ; Fri, 21 May 2021 12:29:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230186AbhEUMav (ORCPT ); Fri, 21 May 2021 08:30:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:56736 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229457AbhEUMat (ORCPT ); Fri, 21 May 2021 08:30:49 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1BC14613DE; Fri, 21 May 2021 12:29:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621600167; bh=1Lfdc7GAV3wIBxxV4DShexmv90ecbDlZxrinOi/ZfJg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Vj692XWhn9NligEBlV+0WnwpLuV187PB7cl9sFIMqiveikX9+AzK1iPT726pczDNQ HSR19wS4Ze3NjE+Z8I9yJH7NQewHRMwaIsR0Fmq5eWJxLZTdU9djhbdseoMat8kGrS kSNjBx+De0K3fU5BVZOiuWPcaexiZDgk4wye9qSW2SUh+YacVJw36Q7Sk+mJLpcQAB cY1V2Y2RTZyvgmjdNQsLSIzeI+HSUdq133aqIdcD5JPCUtasZHcXWZl5vYffZxF0dg s43MrkNruF4Y6AmsUjMbOa9uUM9NtjW6yj1x1Tv9zxay+9Frwsj6fquSvA/YqA9423 SErTb2COM4+kQ== Date: Fri, 21 May 2021 17:59:20 +0530 From: Manivannan Sadhasivam To: Loic Poulain Cc: hemantk@codeaurora.org, linux-arm-msm@vger.kernel.org, bbhatt@codeaurora.org Subject: Re: [PATCH v2] bus: mhi: core: Fix power down latency Message-ID: <20210521122920.GE70095@thinkpad> References: <1620029090-8975-1-git-send-email-loic.poulain@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1620029090-8975-1-git-send-email-loic.poulain@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Mon, May 03, 2021 at 10:04:50AM +0200, Loic Poulain wrote: > On graceful power-down/disable transition, when an MHI reset is > performed, the MHI device loses its context, including interrupt > configuration. However, the current implementation is waiting for > event(irq) driven state change to confirm reset has been completed, > which never happens, and causes reset timeout, leading to unexpected > high latency of the mhi_power_down procedure (up to 45 seconds). > > Fix that by moving to the recently introduced poll_reg_field method, > waiting for the reset bit to be cleared, in the same way as the > power_on procedure. > > Fixes: a6e2e3522f29 ("bus: mhi: core: Add support for PM state transitions") > Signed-off-by: Loic Poulain Reviewed-by: Manivannan Sadhasivam Thanks, Mani > --- > drivers/bus/mhi/core/pm.c | 18 +++++------------- > 1 file changed, 5 insertions(+), 13 deletions(-) > > diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c > index e2e59a3..704a5e2 100644 > --- a/drivers/bus/mhi/core/pm.c > +++ b/drivers/bus/mhi/core/pm.c > @@ -465,23 +465,15 @@ 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; > - unsigned long timeout = msecs_to_jiffies(mhi_cntrl->timeout_ms); > - > dev_dbg(dev, "Triggering MHI Reset in device\n"); > mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET); > > /* Wait for the reset bit to be cleared by the device */ > - ret = wait_event_timeout(mhi_cntrl->state_event, > - mhi_read_reg_field(mhi_cntrl, > - mhi_cntrl->regs, > - MHICTRL, > - MHICTRL_RESET_MASK, > - MHICTRL_RESET_SHIFT, > - &in_reset) || > - !in_reset, timeout); > - if (!ret || in_reset) > - dev_err(dev, "Device failed to exit MHI Reset state\n"); > + ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHICTRL, > + MHICTRL_RESET_MASK, MHICTRL_RESET_SHIFT, 0, > + 25000); > + if (ret) > + dev_err(dev, "Device failed to clear MHI Reset\n"); > > /* > * Device will clear BHI_INTVEC as a part of RESET processing, > -- > 2.7.4 >