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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 1115BC43603 for ; Thu, 19 Dec 2019 18:06:38 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D4CA3227BF for ; Thu, 19 Dec 2019 18:06:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ljJ/C/uy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4CA3227BF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=4P8b7N/KS969nLYGSZPXsbUAzo5Ot3mdX1Qav/7VMLU=; b=ljJ/C/uybs0i+b pv6LI5LfD8uHw2YQPvj0A8vrcijQG5/RlE1YPzGJ+atUJFncpDQRTmNccBklDBZfbIe8JU7taI0or N3uFBBiHQ20tSgYIR2wO2soKpRZp89g/gpO81WsoSfxNx/VnzlXggOFfP4FrC34zTfI8WXvjxfJBN mt+l+f4RS5UsHEdDrDVVARSnWzeb2UG6q+4M0BNFqbFBQ1wuc+ClCA9XKBusZmL5QcIcSaPwFsfsI MFFcoAdSQOAuaLkdyW8O6Kh7AQF4Ip/Y7dP4yXz0wieY6uPjAfCoephcm41m2yH4/ET9P6PApWtgP iutrk9pNhjJSrL/xcUSw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ii0C5-00040E-A9; Thu, 19 Dec 2019 18:06:37 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ii0C1-0003zh-SW for linux-arm-kernel@lists.infradead.org; Thu, 19 Dec 2019 18:06:35 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EE13E1FB; Thu, 19 Dec 2019 10:06:32 -0800 (PST) Received: from bogus (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 199983F67D; Thu, 19 Dec 2019 10:06:30 -0800 (PST) Date: Thu, 19 Dec 2019 18:06:29 +0000 From: Sudeep Holla To: Ulf Hansson Subject: Re: [PATCH v4 13/14] cpuidle: psci: Add support for PM domains by using genpd Message-ID: <20191219180629.GC21846@bogus> References: <20191211154343.29765-1-ulf.hansson@linaro.org> <20191211154343.29765-14-ulf.hansson@linaro.org> <20191219143427.GF20746@bogus> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191219_100634_011079_82F79E86 X-CRM114-Status: GOOD ( 29.21 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Lorenzo Pieralisi , Linux PM , Stephen Boyd , linux-arm-msm , Daniel Lezcano , "Rafael J . Wysocki" , Andy Gross , Lina Iyer , Bjorn Andersson , Kevin Hilman , Rob Herring , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Dec 19, 2019 at 04:48:39PM +0100, Ulf Hansson wrote: > On Thu, 19 Dec 2019 at 15:34, Sudeep Holla wrote: > > > > On Wed, Dec 11, 2019 at 04:43:42PM +0100, Ulf Hansson wrote: > > > When the hierarchical CPU topology layout is used in DT and the PSCI OSI > > > mode is supported by the PSCI FW, let's initialize a corresponding PM > > > domain topology by using genpd. This enables a CPU and a group of CPUs, > > > when attached to the topology, to be power-managed accordingly. > > > > > > To trigger the attempt to initialize the genpd data structures let's use a > > > subsys_initcall, which should be early enough to allow CPUs, but also other > > > devices to be attached. > > > > > > The initialization consists of parsing the PSCI OF node for the topology > > > and the "domain idle states" DT bindings. In case the idle states are > > > compatible with "domain-idle-state", the initialized genpd becomes > > > responsible of selecting an idle state for the PM domain, via assigning it > > > a genpd governor. > > > > > > Note that, a successful initialization of the genpd data structures, is > > > followed by a call to psci_set_osi_mode(), as to try to enable the OSI mode > > > in the PSCI FW. In case this fails, we fall back into a degraded mode > > > rather than bailing out and returning an error code. > > > > > > Co-developed-by: Lina Iyer > > > Signed-off-by: Lina Iyer > > > Signed-off-by: Ulf Hansson > > > --- > > > > > > Changes in v4: > > > - None. > > > > > > --- > > > drivers/cpuidle/cpuidle-psci-domain.c | 267 ++++++++++++++++++++++++++ > > > drivers/cpuidle/cpuidle-psci.c | 4 +- > > > drivers/cpuidle/cpuidle-psci.h | 5 + > > > 3 files changed, 274 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c > > > index 656ef3d59149..c2f94ba42222 100644 > > > --- a/drivers/cpuidle/cpuidle-psci-domain.c > > > +++ b/drivers/cpuidle/cpuidle-psci-domain.c > > > @@ -7,14 +7,281 @@ > > > * > > > */ > > > > > > +#define pr_fmt(fmt) "CPUidle PSCI: " fmt > > > + > > > #include > > > #include > > > #include > > > #include > > > #include > > > +#include > > > +#include > > > +#include > > > > > > #include "cpuidle-psci.h" > > > > > > +struct psci_pd_provider { > > > + struct list_head link; > > > + struct device_node *node; > > > +}; > > > + > > > +static LIST_HEAD(psci_pd_providers); > > > +static bool osi_mode_enabled; > > > + > > > +static int psci_pd_power_off(struct generic_pm_domain *pd) > > > +{ > > > + struct genpd_power_state *state = &pd->states[pd->state_idx]; > > > + u32 *pd_state; > > > + > > > + /* If we have failed to enable OSI mode, then abort power off. */ > > > + if (!osi_mode_enabled) > > > + return -EBUSY; > > > + > > > > Why is above check needed ? Shouldn't we have disable/remove pd of > > OSI is not enabled ? > > Well, failing to enable OSI should in practice not happen, while it > theoretically it could. > I won't assume that. Since it's new and not tested yet, I prefer to assume it can fail. > My approach to this has been to fall back to use a "degraded mode", > which seems quite common for these kind of situations. The degraded > mode means, we are preventing domain states from being used. > But why can't we just fail registering or remove if already added. They are useless for "degraded mode" anyways. And it will ensure that data->dev is NULL. Sorry now I see why you said it can be NULL but I would rather not leave those unused genpd in place in case of error. > More importantly, it also keeps the code registering the PM domains, a > bit simpler. > I feel it is simpler other way around especially if I am testing and seeing failures but I see genpd succeeding. That's confusing. -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel