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 A98ACEE49AE for ; Wed, 23 Aug 2023 07:44:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233512AbjHWHoB (ORCPT ); Wed, 23 Aug 2023 03:44:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233510AbjHWHoA (ORCPT ); Wed, 23 Aug 2023 03:44:00 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 88E71E52; Wed, 23 Aug 2023 00:43:54 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1306D6511C; Wed, 23 Aug 2023 07:43:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DABBDC433C7; Wed, 23 Aug 2023 07:43:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692776633; bh=oK3yV228DJKbwbTXFb4RHff/R+/hOvYP/LBJ/ZoSh30=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kAzSuLjKrRLBN4VfR9xeAelF/xpKdHk+wzqKwaO/hba0tM4UzeZkHmiHxLx6D0gQL /DICzsBbMFRC16rjQw+IOXs5Fu3Mxcbw/6k0xFX6fVTqimBOlQH8ioTTbhWPorP5eF HVJo5EZc3Pc7m6l8r8t5X8F0q2XObe7kWmblm0WiIVKhJbDvCWhG+uWr9YaTvL65N9 cEByENw8+lfaSkDzJPhJTH5ffX4yFI6ap7iqgKvtKX7pCFU1I94cjn4KQGPeQEKpOO JxhimQjOmUoz1vBwWdHVMRtkYew6NlkoTQvs/PZBX7OmGZslAoSNA2Gb66GN+DLLJp XbREhkVVlIc9w== Date: Wed, 23 Aug 2023 13:13:30 +0530 From: Manivannan Sadhasivam To: Jim Quinlan Cc: linux-pci@vger.kernel.org, Nicolas Saenz Julienne , Bjorn Helgaas , Lorenzo Pieralisi , Cyril Brulebois , Phil Elwell , bcm-kernel-feedback-list@broadcom.com, james.quinlan@broadcom.com, Florian Fainelli , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Rob Herring , Krzysztof Kozlowski , Conor Dooley , "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" , "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , open list Subject: Re: [PATCH v5 1/5] dt-bindings: PCI: brcmstb: Add brcm,enable-l1ss property Message-ID: <20230823074330.GF3737@thinkpad> References: <20230508220126.16241-1-jim2101024@gmail.com> <20230508220126.16241-2-jim2101024@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230508220126.16241-2-jim2101024@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, May 08, 2023 at 06:01:21PM -0400, Jim Quinlan wrote: > This commit adds the boolean "brcm,enable-l1ss" property: > > The Broadcom STB/CM PCIe HW -- a core that is also used by RPi SOCs -- > requires the driver probe() to deliberately place the HW one of three > CLKREQ# modes: > > (a) CLKREQ# driven by the RC unconditionally > (b) CLKREQ# driven by the EP for ASPM L0s, L1 > (c) Bidirectional CLKREQ#, as used for L1 Substates (L1SS). > > The HW+driver can tell the difference between downstream devices that > need (a) and (b), but does not know when to configure (c). All devices > should work fine when the driver chooses (a) or (b), but (c) may be > desired to realize the extra power savings that L1SS offers. So we > introduce the boolean "brcm,enable-l1ss" property to inform the driver > that (c) is desired. Setting this property only makes sense when the > downstream device is L1SS-capable and the OS is configured to activate > this mode (e.g. policy==powersupersave). > > This property is already present in the Raspian version of Linux, but the > upstream driver implementation that follows adds more details and > discerns between (a) and (b). > > Signed-off-by: Jim Quinlan > Reviewed-by: Rob Herring > --- > Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml > index 7e15aae7d69e..8b61c2179608 100644 > --- a/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml > +++ b/Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml > @@ -64,6 +64,15 @@ properties: > > aspm-no-l0s: true > > + brcm,enable-l1ss: > + description: Indicates that PCIe L1SS power savings > + are desired, the downstream device is L1SS-capable, and the > + OS has been configured to enable this mode. For boards > + using a mini-card connector, this mode may not meet the > + TCRLon maximum time of 400ns, as specified in 3.2.5.2.2 > + of the PCI Express Mini CEM 2.0 specification. As Lorenzo said, this property doesn't belong in DT. DT is supposed to specify the hardware capability and not system/OS behavior. If this flag specifies whether the PCIe controller supports L1SS or not, then it is fine but apparantly this specifies that all downstream devices are L1SS capable which you cannot guarantee unless you poke into their LNKCAP during runtime. You should handle this in the driver itself. - Mani > + type: boolean > + > brcm,scb-sizes: > description: u64 giving the 64bit PCIe memory > viewport size of a memory controller. There may be up to > -- > 2.17.1 > -- மணிவண்ணன் சதாசிவம் 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 81561EE49AE for ; Wed, 23 Aug 2023 07:44:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc: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=EnUZel8F3fFTP6kYpah++aoWvob3MpkGUpFtJhr+XIo=; b=dn0LKNSSYN7+FG ijnZrxHFiYN4PaMcYJo+GL57nlG3DCAc6SFIxHKKHGt7jzmhrmOHPAzuyc5Sn0UYII0WWzybN5IKY rABsx4hU2h6T2nNVnXRpkTK08K2Nl0l+AOWZCl1+BnH44gS4/+vpEwFnqPxgN18jZ+fYOgC4MM3HH PZvrEAD32UrWsAHBi7SiBAuE6ep61TmCTAQxYI6pdo+/gTwZIUAiURtJzj4EzXC5/sgOArArzqt7l B2BFEKajU1jqnhwEj6aZs+7XDovahozmoEB3s/7kPPP9dJM1b4vf2GIHHdkNQ2ftHdeMCZnLOjxOs /bTgJncBVPppEl10M3uw==; 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charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gTW9uLCBNYXkgMDgsIDIwMjMgYXQgMDY6MDE6MjFQTSAtMDQwMCwgSmltIFF1aW5sYW4gd3Jv dGU6Cj4gVGhpcyBjb21taXQgYWRkcyB0aGUgYm9vbGVhbiAiYnJjbSxlbmFibGUtbDFzcyIgcHJv cGVydHk6Cj4gCj4gICBUaGUgQnJvYWRjb20gU1RCL0NNIFBDSWUgSFcgLS0gYSBjb3JlIHRoYXQg aXMgYWxzbyB1c2VkIGJ5IFJQaSBTT0NzIC0tCj4gICByZXF1aXJlcyB0aGUgZHJpdmVyIHByb2Jl KCkgdG8gZGVsaWJlcmF0ZWx5IHBsYWNlIHRoZSBIVyBvbmUgb2YgdGhyZWUKPiAgIENMS1JFUSMg bW9kZXM6Cj4gCj4gICAoYSkgQ0xLUkVRIyBkcml2ZW4gYnkgdGhlIFJDIHVuY29uZGl0aW9uYWxs eQo+ICAgKGIpIENMS1JFUSMgZHJpdmVuIGJ5IHRoZSBFUCBmb3IgQVNQTSBMMHMsIEwxCj4gICAo YykgQmlkaXJlY3Rpb25hbCBDTEtSRVEjLCBhcyB1c2VkIGZvciBMMSBTdWJzdGF0ZXMgKEwxU1Mp Lgo+IAo+ICAgVGhlIEhXK2RyaXZlciBjYW4gdGVsbCB0aGUgZGlmZmVyZW5jZSBiZXR3ZWVuIGRv d25zdHJlYW0gZGV2aWNlcyB0aGF0Cj4gICBuZWVkIChhKSBhbmQgKGIpLCBidXQgZG9lcyBub3Qg a25vdyB3aGVuIHRvIGNvbmZpZ3VyZSAoYykuICBBbGwgZGV2aWNlcwo+ICAgc2hvdWxkIHdvcmsg ZmluZSB3aGVuIHRoZSBkcml2ZXIgY2hvb3NlcyAoYSkgb3IgKGIpLCBidXQgKGMpIG1heSBiZQo+ ICAgZGVzaXJlZCB0byByZWFsaXplIHRoZSBleHRyYSBwb3dlciBzYXZpbmdzIHRoYXQgTDFTUyBv ZmZlcnMuICBTbyB3ZQo+ICAgaW50cm9kdWNlIHRoZSBib29sZWFuICJicmNtLGVuYWJsZS1sMXNz IiBwcm9wZXJ0eSB0byBpbmZvcm0gdGhlIGRyaXZlcgo+ICAgdGhhdCAoYykgaXMgZGVzaXJlZC4g IFNldHRpbmcgdGhpcyBwcm9wZXJ0eSBvbmx5IG1ha2VzIHNlbnNlIHdoZW4gdGhlCj4gICBkb3du c3RyZWFtIGRldmljZSBpcyBMMVNTLWNhcGFibGUgYW5kIHRoZSBPUyBpcyBjb25maWd1cmVkIHRv IGFjdGl2YXRlCj4gICB0aGlzIG1vZGUgKGUuZy4gcG9saWN5PT1wb3dlcnN1cGVyc2F2ZSkuCj4g Cj4gICBUaGlzIHByb3BlcnR5IGlzIGFscmVhZHkgcHJlc2VudCBpbiB0aGUgUmFzcGlhbiB2ZXJz aW9uIG9mIExpbnV4LCBidXQgdGhlCj4gICB1cHN0cmVhbSBkcml2ZXIgaW1wbGVtZW50YXRpb24g dGhhdCBmb2xsb3dzIGFkZHMgbW9yZSBkZXRhaWxzIGFuZAo+ICAgZGlzY2VybnMgYmV0d2VlbiAo YSkgYW5kIChiKS4KPiAKPiBTaWduZWQtb2ZmLWJ5OiBKaW0gUXVpbmxhbiA8amltMjEwMTAyNEBn bWFpbC5jb20+Cj4gUmV2aWV3ZWQtYnk6IFJvYiBIZXJyaW5nIDxyb2JoQGtlcm5lbC5vcmc+Cj4g LS0tCj4gIERvY3VtZW50YXRpb24vZGV2aWNldHJlZS9iaW5kaW5ncy9wY2kvYnJjbSxzdGItcGNp ZS55YW1sIHwgOSArKysrKysrKysKPiAgMSBmaWxlIGNoYW5nZWQsIDkgaW5zZXJ0aW9ucygrKQo+ IAo+IGRpZmYgLS1naXQgYS9Eb2N1bWVudGF0aW9uL2RldmljZXRyZWUvYmluZGluZ3MvcGNpL2Jy Y20sc3RiLXBjaWUueWFtbCBiL0RvY3VtZW50YXRpb24vZGV2aWNldHJlZS9iaW5kaW5ncy9wY2kv YnJjbSxzdGItcGNpZS55YW1sCj4gaW5kZXggN2UxNWFhZTdkNjllLi44YjYxYzIxNzk2MDggMTAw NjQ0Cj4gLS0tIGEvRG9jdW1lbnRhdGlvbi9kZXZpY2V0cmVlL2JpbmRpbmdzL3BjaS9icmNtLHN0 Yi1wY2llLnlhbWwKPiArKysgYi9Eb2N1bWVudGF0aW9uL2RldmljZXRyZWUvYmluZGluZ3MvcGNp L2JyY20sc3RiLXBjaWUueWFtbAo+IEBAIC02NCw2ICs2NCwxNSBAQCBwcm9wZXJ0aWVzOgo+ICAK PiAgICBhc3BtLW5vLWwwczogdHJ1ZQo+ICAKPiArICBicmNtLGVuYWJsZS1sMXNzOgo+ICsgICAg ZGVzY3JpcHRpb246IEluZGljYXRlcyB0aGF0IFBDSWUgTDFTUyBwb3dlciBzYXZpbmdzCj4gKyAg ICAgIGFyZSBkZXNpcmVkLCB0aGUgZG93bnN0cmVhbSBkZXZpY2UgaXMgTDFTUy1jYXBhYmxlLCBh bmQgdGhlCj4gKyAgICAgIE9TIGhhcyBiZWVuIGNvbmZpZ3VyZWQgdG8gZW5hYmxlIHRoaXMgbW9k ZS4gIEZvciBib2FyZHMKPiArICAgICAgdXNpbmcgYSBtaW5pLWNhcmQgY29ubmVjdG9yLCB0aGlz IG1vZGUgbWF5IG5vdCBtZWV0IHRoZQo+ICsgICAgICBUQ1JMb24gbWF4aW11bSB0aW1lIG9mIDQw MG5zLCBhcyBzcGVjaWZpZWQgaW4gMy4yLjUuMi4yCj4gKyAgICAgIG9mIHRoZSBQQ0kgRXhwcmVz cyBNaW5pIENFTSAyLjAgc3BlY2lmaWNhdGlvbi4KCkFzIExvcmVuem8gc2FpZCwgdGhpcyBwcm9w ZXJ0eSBkb2Vzbid0IGJlbG9uZyBpbiBEVC4gRFQgaXMgc3VwcG9zZWQgdG8gc3BlY2lmeQp0aGUg aGFyZHdhcmUgY2FwYWJpbGl0eSBhbmQgbm90IHN5c3RlbS9PUyBiZWhhdmlvci4gSWYgdGhpcyBm bGFnIHNwZWNpZmllcwp3aGV0aGVyIHRoZSBQQ0llIGNvbnRyb2xsZXIgc3VwcG9ydHMgTDFTUyBv ciBub3QsIHRoZW4gaXQgaXMgZmluZSBidXQgYXBwYXJhbnRseQp0aGlzIHNwZWNpZmllcyB0aGF0 IGFsbCBkb3duc3RyZWFtIGRldmljZXMgYXJlIEwxU1MgY2FwYWJsZSB3aGljaCB5b3UgY2Fubm90 Cmd1YXJhbnRlZSB1bmxlc3MgeW91IHBva2UgaW50byB0aGVpciBMTktDQVAgZHVyaW5nIHJ1bnRp bWUuCgpZb3Ugc2hvdWxkIGhhbmRsZSB0aGlzIGluIHRoZSBkcml2ZXIgaXRzZWxmLgoKLSBNYW5p Cgo+ICsgICAgdHlwZTogYm9vbGVhbgo+ICsKPiAgICBicmNtLHNjYi1zaXplczoKPiAgICAgIGRl c2NyaXB0aW9uOiB1NjQgZ2l2aW5nIHRoZSA2NGJpdCBQQ0llIG1lbW9yeQo+ICAgICAgICB2aWV3 cG9ydCBzaXplIG9mIGEgbWVtb3J5IGNvbnRyb2xsZXIuICBUaGVyZSBtYXkgYmUgdXAgdG8KPiAt LSAKPiAyLjE3LjEKPiAKCi0tIArgrq7grqPgrr/grrXgrqPgr43grqPgrqngr40g4K6a4K6k4K6+ 4K6a4K6/4K614K6u4K+NCgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fXwpsaW51eC1hcm0ta2VybmVsIG1haWxpbmcgbGlzdApsaW51eC1hcm0ta2VybmVsQGxp c3RzLmluZnJhZGVhZC5vcmcKaHR0cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9saXN0 aW5mby9saW51eC1hcm0ta2VybmVsCg==