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 E3A25C433FE for ; Thu, 3 Nov 2022 12:35:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230423AbiKCMe7 (ORCPT ); Thu, 3 Nov 2022 08:34:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230194AbiKCMe6 (ORCPT ); Thu, 3 Nov 2022 08:34:58 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49D4EBF44; Thu, 3 Nov 2022 05:34:57 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id DBD9EB82531; Thu, 3 Nov 2022 12:34:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2EB3EC433D7; Thu, 3 Nov 2022 12:34:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1667478894; bh=kwC8c9iT4n97Y2z/Aic1ez2OXO1eBSULeJPMuCVAFHk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=i+lBS+leXHEf+hVhQsl2MUuothos7zrXn3fV78WVA7Rz1NdP++RewaodJWcx0wGqw KNJOiKhjMHxW91ky6p7QwsCMz3/TVgfyO0C1895eCJXJL0jU3DxtzB7RgH6k3C2vMe ASP6ieuPaYsu3NlxmoOL2d0r+fazbakWt8HIBOpOSQzmSnicSCbj/0oHG0dcBdUwWw S6CHDDGkCIEa/lBwbsZEmES6GKVK5XZ2afcSajObfyNZlXwBQJS8IzvhT1++nKxh5I 58KiqO4Ffz/96ArZM0fbkHj8xo6ZHla8KXJAmBb5NAAzmro5wAhgc2gG4mV6k76EoG QLARRfpFtkaWA== Date: Thu, 3 Nov 2022 18:04:44 +0530 From: Manivannan Sadhasivam To: Johan Hovold Cc: Lorenzo Pieralisi , stanimir.k.varbanov@gmail.com, Andy Gross , Bjorn Andersson , Konrad Dybcio , Bjorn Helgaas , Rob Herring , Krzysztof Kozlowski , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Brian Masney , linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Georgi Djakov Subject: Re: [PATCH v3 2/2] PCI: qcom: Add basic interconnect support Message-ID: <20221103123444.GE8434@thinkpad> References: <20221102090705.23634-1-johan+linaro@kernel.org> <20221102090705.23634-3-johan+linaro@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20221102090705.23634-3-johan+linaro@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Nov 02, 2022 at 10:07:05AM +0100, Johan Hovold wrote: > On Qualcomm platforms like SC8280XP and SA8540P, interconnect bandwidth > must be requested before enabling interconnect clocks. > > Add basic support for managing an optional "pcie-mem" interconnect path > by setting a low constraint before enabling clocks and updating it after > the link is up. > > Note that it is not possible for a controller driver to set anything but > a maximum peak bandwidth as expected average bandwidth will vary with > use case and actual use (and power policy?). This very much remains an > unresolved problem with the interconnect framework. > > Also note that no constraint is set for the SC8280XP/SA8540P "cpu-pcie" > path for now as it is not clear what an appropriate constraint would be > (and the system does not crash when left unspecified). > > Fixes: 70574511f3fc ("PCI: qcom: Add support for SC8280XP") > Reviewed-by: Brian Masney > Acked-by: Georgi Djakov > Signed-off-by: Johan Hovold Reviewed-by: Manivannan Sadhasivam Thanks, Mani > --- > drivers/pci/controller/dwc/pcie-qcom.c | 76 ++++++++++++++++++++++++++ > 1 file changed, 76 insertions(+) > > diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c > index 7db94a22238d..91b113d0c02a 100644 > --- a/drivers/pci/controller/dwc/pcie-qcom.c > +++ b/drivers/pci/controller/dwc/pcie-qcom.c > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -224,6 +225,7 @@ struct qcom_pcie { > union qcom_pcie_resources res; > struct phy *phy; > struct gpio_desc *reset; > + struct icc_path *icc_mem; > const struct qcom_pcie_cfg *cfg; > }; > > @@ -1644,6 +1646,74 @@ static const struct dw_pcie_ops dw_pcie_ops = { > .start_link = qcom_pcie_start_link, > }; > > +static int qcom_pcie_icc_init(struct qcom_pcie *pcie) > +{ > + struct dw_pcie *pci = pcie->pci; > + int ret; > + > + pcie->icc_mem = devm_of_icc_get(pci->dev, "pcie-mem"); > + if (IS_ERR(pcie->icc_mem)) > + return PTR_ERR(pcie->icc_mem); > + > + /* > + * Some Qualcomm platforms require interconnect bandwidth constraints > + * to be set before enabling interconnect clocks. > + * > + * Set an initial peak bandwidth corresponding to single-lane Gen 1 > + * for the pcie-mem path. > + */ > + ret = icc_set_bw(pcie->icc_mem, 0, MBps_to_icc(250)); > + if (ret) { > + dev_err(pci->dev, "failed to set interconnect bandwidth: %d\n", > + ret); > + return ret; > + } > + > + return 0; > +} > + > +static void qcom_pcie_icc_update(struct qcom_pcie *pcie) > +{ > + struct dw_pcie *pci = pcie->pci; > + u32 offset, status, bw; > + int speed, width; > + int ret; > + > + if (!pcie->icc_mem) > + return; > + > + offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); > + status = readw(pci->dbi_base + offset + PCI_EXP_LNKSTA); > + > + /* Only update constraints if link is up. */ > + if (!(status & PCI_EXP_LNKSTA_DLLLA)) > + return; > + > + speed = FIELD_GET(PCI_EXP_LNKSTA_CLS, status); > + width = FIELD_GET(PCI_EXP_LNKSTA_NLW, status); > + > + switch (speed) { > + case 1: > + bw = MBps_to_icc(250); > + break; > + case 2: > + bw = MBps_to_icc(500); > + break; > + default: > + WARN_ON_ONCE(1); > + fallthrough; > + case 3: > + bw = MBps_to_icc(985); > + break; > + } > + > + ret = icc_set_bw(pcie->icc_mem, 0, width * bw); > + if (ret) { > + dev_err(pci->dev, "failed to set interconnect bandwidth: %d\n", > + ret); > + } > +} > + > static int qcom_pcie_probe(struct platform_device *pdev) > { > struct device *dev = &pdev->dev; > @@ -1704,6 +1774,10 @@ static int qcom_pcie_probe(struct platform_device *pdev) > goto err_pm_runtime_put; > } > > + ret = qcom_pcie_icc_init(pcie); > + if (ret) > + goto err_pm_runtime_put; > + > ret = pcie->cfg->ops->get_resources(pcie); > if (ret) > goto err_pm_runtime_put; > @@ -1722,6 +1796,8 @@ static int qcom_pcie_probe(struct platform_device *pdev) > goto err_phy_exit; > } > > + qcom_pcie_icc_update(pcie); > + > return 0; > > err_phy_exit: > -- > 2.37.3 > -- மணிவண்ணன் சதாசிவம்