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 2ED02C433FE for ; Tue, 17 May 2022 15:11:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229492AbiEQPLr (ORCPT ); Tue, 17 May 2022 11:11:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57868 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349703AbiEQPLp (ORCPT ); Tue, 17 May 2022 11:11:45 -0400 Received: from mail-pl1-x62b.google.com (mail-pl1-x62b.google.com [IPv6:2607:f8b0:4864:20::62b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1A653BFB0 for ; Tue, 17 May 2022 08:11:43 -0700 (PDT) Received: by mail-pl1-x62b.google.com with SMTP id d17so17624469plg.0 for ; Tue, 17 May 2022 08:11:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=cmLXabcPdJC5+Jr+geeae2kzppnXJw8ILHcl1Qm7vBw=; b=CMbAPHf6t+S5Kg1C4GszZxleCRPzPCJZatJ1Uhgf4vk0o6lS847ZRTFjB8hGXzHMWl ll+/Pk58qJPLoniMeyG8G08xqU5f8Y1cYHkaDkQ68EI4RSuceZvg8L88QzT3nG1ggMQh wpCPXtWUjd3VPVCZAzB0zNj9VYjpBbBGN0i5lSZugdLoFWYUYY403CgSeaPvbw/GJWfo KoWb+QmOkyIhZFiG13zp7J2QOwQr5UeggVUWxzffet1NnT0TxQlosvVe3iY8p187yVk4 PGriacZsHbGjO6/cFvWrqRlURZJrIBSd0FdYh8B5fOKv/rRpHcFyySilRPJurX8HmkZ+ GF4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=cmLXabcPdJC5+Jr+geeae2kzppnXJw8ILHcl1Qm7vBw=; b=Ve//Sf7nprofLruog+1ZnXjCeDikrVh4thwe/VzM0q011idgW5tHuQl3I0P2p0wZFC iULN5XMl7tSlyNAA8yD0XSyCKzMTnXzXFXQMB5RnZoWvtt0N8k+sue1pDrWGQzCtqGMV 1BU3J1Uy7SskHhfhqP/ajbf/JXRYNTqE1H0yYoCY6icUSdXGxfg7PhqzevSktYjxUvnA kKCBIxgUwQ8GjC66DT2QypFdGiWJ0ctc3skw2p9SsZhMxGR65Hwh3nMPM6xZVDy5tzCo Q5ZN/mEMOyUjSXCyecQk8vxmrGSFwNZytKlLBEZog2ROBqcGMrMpUddZncoBfa0Trkyc oMkw== X-Gm-Message-State: AOAM530nWFgqt5UStBTldIdx2zrGQDm9Vnz+2Q6u5O2yEEIPn1LKjmE4 VPYz+kFRFI5G9vDSGwG/Tf7u X-Google-Smtp-Source: ABdhPJy/8+de+j926ut7sfC02FyPhUMi0LcfxLj34YwOAks7Rl82lL4Rj6Y5maOSEeF2PjT7605A/g== X-Received: by 2002:a17:902:dad1:b0:161:9abb:fb75 with SMTP id q17-20020a170902dad100b001619abbfb75mr6145785plx.135.1652800303244; Tue, 17 May 2022 08:11:43 -0700 (PDT) Received: from thinkpad ([117.207.31.8]) by smtp.gmail.com with ESMTPSA id ja1-20020a170902efc100b001617e18e253sm4280263plb.143.2022.05.17.08.11.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 May 2022 08:11:42 -0700 (PDT) Date: Tue, 17 May 2022 20:41:34 +0530 From: Manivannan Sadhasivam To: Bjorn Helgaas Cc: bhelgaas@google.com, lorenzo.pieralisi@arm.com, kbusch@kernel.org, hch@lst.de, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, svarbanov@mm-sol.com, bjorn.andersson@linaro.org, axboe@fb.com, quic_vbadigan@quicinc.com, quic_krichai@quicinc.com, quic_nitirawa@quicinc.com, vidyas@nvidia.com, sagi@grimberg.me Subject: Re: [PATCH 2/3] PCI: dwc: qcom: Set suspend_poweroff flag for SC7280 Message-ID: <20220517151134.GB4528@thinkpad> References: <20220513110027.31015-3-manivannan.sadhasivam@linaro.org> <20220516201950.GA1047412@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220516201950.GA1047412@bhelgaas> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, May 16, 2022 at 03:19:50PM -0500, Bjorn Helgaas wrote: > On Fri, May 13, 2022 at 04:30:26PM +0530, Manivannan Sadhasivam wrote: > > For aggressive power saving on SC7280 SoCs, the power for the PCI devices > > will be taken off during system suspend. Hence, notify the same to the > > PCI device drivers using "suspend_poweroff" flag so that the drivers can > > prepare the PCI devices to handle the poweroff and recover them during > > resume. > > No doubt "power ... will be taken off during system suspend" is true, > but this isn't very informative. Is this a property of SC7280? A > choice made by the SC7280 driver? Why is this not applicable to other > systems? > The SC7280's RPMh firmware is cutting off the PCIe power domain during system suspend. And as I explained in previous patch, the RC driver itself may put the devices in D3cold conditionally on this platform. The reason is to save power as this chipset is being used in Chromebooks. Thanks, Mani > > Signed-off-by: Manivannan Sadhasivam > > --- > > drivers/pci/controller/dwc/pcie-qcom.c | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c > > index 6ab90891801d..4b0ad2827f8f 100644 > > --- a/drivers/pci/controller/dwc/pcie-qcom.c > > +++ b/drivers/pci/controller/dwc/pcie-qcom.c > > @@ -199,6 +199,7 @@ struct qcom_pcie_cfg { > > unsigned int has_ddrss_sf_tbu_clk:1; > > unsigned int has_aggre0_clk:1; > > unsigned int has_aggre1_clk:1; > > + unsigned int suspend_poweroff:1; > > }; > > > > struct qcom_pcie { > > @@ -1220,6 +1221,10 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie) > > if (pcie->cfg->pipe_clk_need_muxing) > > clk_set_parent(res->pipe_clk_src, res->ref_clk_src); > > > > + /* Indicate PCI device drivers that the power will be taken off during system suspend */ > > + if (pcie->cfg->suspend_poweroff) > > + pci->pp.bridge->suspend_poweroff = true; > > + > > ret = clk_bulk_prepare_enable(res->num_clks, res->clks); > > if (ret < 0) > > goto err_disable_regulators; > > @@ -1548,6 +1553,7 @@ static const struct qcom_pcie_cfg sc7280_cfg = { > > .ops = &ops_1_9_0, > > .has_tbu_clk = true, > > .pipe_clk_need_muxing = true, > > + .suspend_poweroff = true, > > }; > > > > static const struct dw_pcie_ops dw_pcie_ops = { > > -- > > 2.25.1 > > -- மணிவண்ணன் சதாசிவம்