linux-kernel - Re: [PATCH v2 2/4] dt-bindings: Add 'slot-power-limit-milliwatt' PCIe port property

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <YjzY2wUg9SrDzHND@robh.at.kernel.org>
Date:   Thu, 24 Mar 2022 15:47:23 -0500
From:   Rob Herring <robh@...nel.org>
To:     Pali Rohár <pali@...nel.org>
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Andrew Lunn <andrew@...n.ch>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Marek Behún <kabel@...nel.org>,
        Russell King <rmk+kernel@...linux.org.uk>,
        linux-pci@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/4] dt-bindings: Add 'slot-power-limit-milliwatt'
 PCIe port property

On Wed, Mar 02, 2022 at 03:57:31PM +0100, Pali Rohár wrote:
> This property specifies slot power limit in mW unit. It is a form-factor
> and board specific value and must be initialized by hardware.
> 
> Some PCIe controllers delegate this work to software to allow hardware
> flexibility and therefore this property basically specifies what should
> host bridge program into PCIe Slot Capabilities registers.
> 
> The property needs to be specified in mW unit instead of the special format
> defined by Slot Capabilities (which encodes scaling factor or different
> unit). Host drivers should convert the value from mW to needed format.
> 
> Signed-off-by: Pali Rohár <pali@...nel.org>
> Signed-off-by: Marek Behún <kabel@...nel.org>
> 
> ---
> This change was already accepted into dt-schema repo by Rob Herring:
> https://github.com/devicetree-org/dt-schema/pull/66

Which is the definitive source for it. pci.txt should shrink or be 
removed, not added to.

> ---
>  Documentation/devicetree/bindings/pci/pci.txt | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt
> index 6a8f2874a24d..b0cc133ed00d 100644
> --- a/Documentation/devicetree/bindings/pci/pci.txt
> +++ b/Documentation/devicetree/bindings/pci/pci.txt
> @@ -32,6 +32,12 @@ driver implementation may support the following properties:
>     root port to downstream device and host bridge drivers can do programming
>     which depends on CLKREQ signal existence. For example, programming root port
>     not to advertise ASPM L1 Sub-States support if there is no CLKREQ signal.
> +- slot-power-limit-milliwatt:
> +   If present, this property specifies slot power limit in milliwatts. Host
> +   drivers can parse this property and use it for programming Root Port or host
> +   bridge, or for composing and sending PCIe Set_Slot_Power_Limit messages
> +   through the Root Port or host bridge when transitioning PCIe link from a
> +   non-DL_Up Status to a DL_Up Status.
>  
>  PCI-PCI Bridge properties
>  -------------------------
> -- 
> 2.20.1
>