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=-16.3 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 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 D7760C433E6 for ; Tue, 9 Mar 2021 16:47:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B37AA65237 for ; Tue, 9 Mar 2021 16:47:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230464AbhCIQq7 (ORCPT ); Tue, 9 Mar 2021 11:46:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:47558 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230465AbhCIQqo (ORCPT ); Tue, 9 Mar 2021 11:46:44 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2603A6523C; Tue, 9 Mar 2021 16:46:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615308404; bh=RMuhxlWDr/r4WRIMBjUfGXkdUAHrO0I8oA8IyU3VFFE=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=ARjXIRzW1QTmrBj4oKD8skJteEymA+z/2M7i8AfLGwdsFqzQ7G1/ziAc+LX4BxVKk AkzSp4ZpHyIVYodLKh9oZAw/WPGyOvj9EyuFGaIhZxnRRzMfwo+u27hLIcEn4Ex8Qy FGdcxm0JsYuadm3V7eaJoH9b6Sm49jlWdBtg4Cphszrt6nHWHYR8/U52cVZsb6KA9q OsWwmatkgmcMqCwmTMBVn3gs6iQTlF0A5Ea9o9uB2lDr7m2BY5kM3sLkeCVO5n+owx t+BLwi2eQUx4iR6ktE0/iHOyYFWBsvGJ7SAIrZ8vwjA62DRNfSfhvFS66nXSVmnWuU YwmSP581kulFg== Received: by mail-ed1-f44.google.com with SMTP id b13so21578666edx.1; Tue, 09 Mar 2021 08:46:44 -0800 (PST) X-Gm-Message-State: AOAM533/BAE5JtfuN5BOzCHTGZ+bYD9nMBpxlDpiClRHJ7XJL8Hax9tH 6DFojF9aPu8dRrBvPnY8WxjHngZT/H86v6/GsA== X-Google-Smtp-Source: ABdhPJyEb71X8b4Z+MqyVeM6DPC6hgj3zw9kIgCbE/MTLqqs0cnJzMorzefBS1R28UIUW2kwGB6bbNEoNb9+T3Y7jEs= X-Received: by 2002:a05:6402:c88:: with SMTP id cm8mr5184509edb.62.1615308402777; Tue, 09 Mar 2021 08:46:42 -0800 (PST) MIME-Version: 1.0 References: <20210309073142.13219-1-nadeem@cadence.com> <20210309073142.13219-2-nadeem@cadence.com> In-Reply-To: <20210309073142.13219-2-nadeem@cadence.com> From: Rob Herring Date: Tue, 9 Mar 2021 09:46:30 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 1/2] dt-bindings:pci: Set LTSSM Detect.Quiet state delay. To: Nadeem Athani Cc: Tom Joseph , Bjorn Helgaas , PCI , devicetree@vger.kernel.org, "linux-kernel@vger.kernel.org" , Lorenzo Pieralisi , Kishon Vijay Abraham I , Milind Parab , Swapnil Kashinath Jakhade , Parshuram Raju Thombare Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Tue, Mar 9, 2021 at 12:31 AM Nadeem Athani wrote: > > The parameter detect-quiet-min-delay can be used to program the minimum > time that LTSSM waits on entering Detect.Quiet state. > 00 : 0us minimum wait time in Detect.Quiet state. > 01 : 100us minimum wait time in Detect.Quiet state. > 10 : 1000us minimum wait time in Detect.Quiet state. > 11 : 2000us minimum wait time in Detect.Quiet state. What determines this setting? Is it per board or SoC? Is this a standard PCI timing thing? Why does this need to be tuned per platform? > Signed-off-by: Nadeem Athani > --- > .../devicetree/bindings/pci/cdns,cdns-pcie-host.yaml | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/Documentation/devicetree/bindings/pci/cdns,cdns-pcie-host.yaml b/Documentation/devicetree/bindings/pci/cdns,cdns-pcie-host.yaml > index 293b8ec318bc..a1d56e0be419 100644 > --- a/Documentation/devicetree/bindings/pci/cdns,cdns-pcie-host.yaml > +++ b/Documentation/devicetree/bindings/pci/cdns,cdns-pcie-host.yaml > @@ -27,6 +27,18 @@ properties: > > msi-parent: true > > + detect-quiet-min-delay: > + description: > + LTSSM Detect.Quiet state minimum delay. > + 00 : 0us minimum wait time > + 01 : 100us minimum wait time > + 10 : 1000us minimum wait time > + 11 : 2000us minimum wait time > + $ref: /schemas/types.yaml#/definitions/uint32 > + minimum: 0 > + maximum: 3 > + default: 0 > + > required: > - reg > - reg-names > @@ -48,6 +60,7 @@ examples: > linux,pci-domain = <0>; > vendor-id = <0x17cd>; > device-id = <0x0200>; > + detect-quiet-min-delay = <0>; > > reg = <0x0 0xfb000000 0x0 0x01000000>, > <0x0 0x41000000 0x0 0x00001000>; > -- > 2.15.0 >