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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3B5BECAAA1 for ; Tue, 30 Aug 2022 18:44:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231424AbiH3SoF (ORCPT ); Tue, 30 Aug 2022 14:44:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231342AbiH3SoC (ORCPT ); Tue, 30 Aug 2022 14:44:02 -0400 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2CF057436B for ; Tue, 30 Aug 2022 11:44:00 -0700 (PDT) Received: by mail-pf1-x42b.google.com with SMTP id q15so6835507pfn.11 for ; Tue, 30 Aug 2022 11:44:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc; bh=NZVZkfFYq+g48u9ab87ZWo6dPBjM06Q+lLAU8Yvk5EA=; b=Axzf/shUDMALwg8iHDSJOsle0Qw6yo7nQ4L0Ew2LPymFZnPev4UAjpWJldbz1gztDq jKZJw7kpHpXifWeb417pif3gyrl7IsgOi9WFU3RwiXyuvYeVh5uByAISbNeGVLzQ7MTp gueWsarra0u8xd3OAbrUmHKAixAZjsKVVwK1g= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc; bh=NZVZkfFYq+g48u9ab87ZWo6dPBjM06Q+lLAU8Yvk5EA=; b=qqhWndmo3oySBvRxzEw6leMX5139VZboaT70M4dQAn79r3nHwm5OIJ8hm4imyics0F abKRzJjl4p9RzKaEWeTmdyolrZ+DrslfudSzENNH52apPWnS/V5gFae19eEhy92XXmRb vtUAnfo7BRAhgbEWjMP0Hx/3Iq/kSeJGPTDbK+FL9OrExJTkFHneVN02Whn6O1IO6etd AwAIVlV3D42xqQHqgSfbfaIzE+9XgB2TKjfpRoH4BmIyQfkm4p+nyyxdZbUFQoopH157 aouNh3I7bVyLE3L9YfrataXMUB7fDZyD+TYqJmNEbW8+RZjBbvRzb4LTkidPwcSocxbe eYXw== X-Gm-Message-State: ACgBeo3AXqOdYNJhEEPXaQXx8mOjqb0uh2BdMhOhsid0XM5ospHOvd4I 1E/IN5mt50wub4m/5MvAioTB5g== X-Google-Smtp-Source: AA6agR7zpTyvcECkA2jQOB4My7timJiRT9otT5h6XOP4Y4xqijtClzf1Ffy2uOmONrciFnSEmceaNw== X-Received: by 2002:a63:1841:0:b0:429:8268:1fc with SMTP id 1-20020a631841000000b00429826801fcmr19102261pgy.78.1661885039627; Tue, 30 Aug 2022 11:43:59 -0700 (PDT) Received: from localhost ([2620:15c:11a:202:f023:bd53:48bf:f508]) by smtp.gmail.com with UTF8SMTPSA id b11-20020a170902d50b00b0016dc2366722sm10163636plg.77.2022.08.30.11.43.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 30 Aug 2022 11:43:59 -0700 (PDT) Date: Tue, 30 Aug 2022 11:43:57 -0700 From: Matthias Kaehlcke To: Rajendra Nayak Cc: Bjorn Andersson , Andy Gross , Konrad Dybcio , Michael Turquette , Stephen Boyd , Johan Hovold , linux-clk@vger.kernel.org, Krishna Kurapati , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Douglas Anderson , Bjorn Andersson Subject: Re: [PATCH v2 1/2] clk: qcom: gcc-sc7180: Keep the USB GDSC always on Message-ID: References: <20220825182152.v2.1.I45235b7c40997bc2abf813e4722b4dcdd6aecf6b@changeid> <20220826024003.qpqtdmdohdmpcskt@baldur> <5ff21b1e-3af9-36ef-e13e-fa33f526d0e3@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <5ff21b1e-3af9-36ef-e13e-fa33f526d0e3@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 29, 2022 at 01:42:02PM +0530, Rajendra Nayak wrote: > > On 8/26/2022 8:10 AM, Bjorn Andersson wrote: > > On Thu, Aug 25, 2022 at 06:21:58PM -0700, Matthias Kaehlcke wrote: > > > When the GDSC is disabled during system suspend USB is broken on > > > sc7180 when the system resumes. Mark the GDSC as always on to > > > make sure USB still works after system suspend. > > > > > > Signed-off-by: Matthias Kaehlcke > > > > Rajendra, where you able to find some time to look into take the GDSC > > into retention state? Do you suggest that I merge these two patches for > > now? > > > > Hi Bjorn, based on my experiments to support retention on sc7280 these are > some of my findings > > On Platforms which support CX retention (for example sc7180/sc7280) instead of > CX PowerCollapse (PC), We can leave the GDSC turned ON. When CX transitions to RET state > the GDSC goes into retention too (some controller state is retained) and USB wakeups work. > > On platforms which support CX PC, just leaving the GDSC > turned ON will not help since the GDSC will also transition to OFF state > when we enter CX PC, hence wake-ups from USB won't work. > For such platforms we need to make sure gdsc_force_mem_on() is called > and cxcs (* @cxcs: offsets of branch registers to toggle mem/periph bits in) > are populated correctly, while leaving the GDSC turned ON. > This will make sure usb gdsc transitions from being powered by CX to MX > when CX hits PC and we still get USB wakeups to work. > So in short we could do the same thing that this patch does on those > platforms too with additionally populating the right cxcs entries and it > should just work fine. > > Now the problem that I see with this approach is not with getting USB wakeups > to work in suspend, but with supporting performance state voting when > USB is active. > The last conclusion we had on that [1] was to model usb_gdsc as a subdomain of CX, > so if we do that and we model usb_gdsc as something that supports ALWAYS_ON, > we would _never_ drop the CX vote and prevent CX from going down (either to ret > or pc) > > The only way I think we can solve both the USB wakeups and performance state > needs (with usb_gdsc as a subdomain of CX) is if we can model a RET state for gdsc > which sets the mem/periph bits while leaving the GDSC ON (Today the RET state sets > the mem/periph bits but turns the GDSC OFF) > > That would mean a change in gdsc.c like this > --- > > diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c > index d3244006c661..0fe017ba901b 100644 > --- a/drivers/clk/qcom/gdsc.c > +++ b/drivers/clk/qcom/gdsc.c > @@ -368,6 +368,10 @@ static int _gdsc_disable(struct gdsc *sc) > if (sc->pwrsts & PWRSTS_OFF) > gdsc_clear_mem_on(sc); > > + /* If the GDSC supports RET, do not explicitly power it off */ > + if (sc->pwrsts & PWRSTS_RET) > + return 0; > + > ret = gdsc_toggle_logic(sc, GDSC_OFF); > if (ret) > return ret; > > > So with that change, we would then not need the ALWAYS_ON flag set for usb gdsc, > instead we would update the .pwrsts to PWRSTS_RET_ON instead of PWRSTS_OFF_ON, > and that should make both usb wake-ups to work and we can still have the usb_gdsc as > a subdomain of CX for performance state voting. Krishna and I confirmed that this works from the USB side for sc7180 and sc7280.