Message-ID: <20220522174334.cnguiyl7u3nhe7mm@mobilestation>
Date:   Sun, 22 May 2022 20:43:34 +0300
From:   Serge Semin <fancer.lancer@...il.com>
To:     Rob Herring <robh@...nel.org>
Cc:     Serge Semin <Sergey.Semin@...kalelectronics.ru>,
        Damien Le Moal <damien.lemoal@...nsource.wdc.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Jens Axboe <axboe@...nel.dk>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>,
        Pavel Parkhomenko <Pavel.Parkhomenko@...kalelectronics.ru>,
        linux-ide@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v3 12/23] dt-bindings: ata: ahci: Add platform capability
 properties

On Tue, May 17, 2022 at 02:20:28PM -0500, Rob Herring wrote:
> On Thu, May 12, 2022 at 02:17:59AM +0300, Serge Semin wrote:
> > In case if the platform doesn't have BIOS or a comprehensive firmware
> > installed then the HBA capability flags will be left uninitialized. As a
> > good alternative we can define a set AHCI DT-node properties to describe
> > all of HW-init capabilities flags. Luckily there aren't too many of them.
> > SSS - Staggered Spin-up support and MPS - Mechanical Presence Switch
> > support determine the corresponding feature availability for whole HBA by
> > means of the "hba-sss" and "hba-smps" properties.  Each port can have the
> > "hba-{hpcp,mpsp,cpd,esp,fbscp}" defined indicatating that the port
> > supports the next functionality: HPCP - HotPlug capable port, MPSP -
> > Mechanical Presence Switch attached to a port, CPD - Cold Plug detection,
> > ESP - External SATA Port (eSATA), FBSCP - FIS-based switching capable
> > port.
> > 
> > Signed-off-by: Serge Semin <Sergey.Semin@...kalelectronics.ru>
> > 
> > ---
> > 
> > Alternatively we could define them as a bitfield, but having a set of
> > boolean properties seemed a better idea since in that case we can
> > implement a simple inter-dependency rules for them, which can't be done
> > should we take the bitfields path.
> 

> I would just provide a CAP register override and be done with it.
> 
> The boolean fields only let you set a capability, but not unset one. 
> They would need to be tristate.

Ok. I'll convert the boolean properties to the generic (hba-cap) and
per-port (hba-port-cap) properties with CAP-override fields.

-Sergey

> 
> > ---
> >  .../devicetree/bindings/ata/ahci-common.yaml  | 66 +++++++++++++++++++
> >  .../bindings/ata/ahci-platform.yaml           | 11 ++++
> >  2 files changed, 77 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/ata/ahci-common.yaml b/Documentation/devicetree/bindings/ata/ahci-common.yaml
> > index a7d1a8353de3..a29edfbb25db 100644
> > --- a/Documentation/devicetree/bindings/ata/ahci-common.yaml
> > +++ b/Documentation/devicetree/bindings/ata/ahci-common.yaml
> > @@ -75,6 +75,19 @@ properties:
> >    phy-names:
> >      const: sata-phy
> >  
> > +  hba-sss:
> > +    type: boolean
> > +    description:
> > +      Staggered Spin-up Support. Indicates whether the HBA supports the
> > +      staggered spin-up on its ports, for use in balancing power spikes.
> > +
> > +  hba-smps:
> > +    type: boolean
> > +    description:
> > +      Mechanical Presence Switch Support. Indicates whether the HBA supports
> > +      mechanical presence switches on its ports for use in hot plug
> > +      operations.
> > +
> >    ports-implemented:
> >      $ref: '/schemas/types.yaml#/definitions/uint32'
> >      description:
> > @@ -97,6 +110,40 @@ patternProperties:
> >          minimum: 0
> >          maximum: 31
> >  
> > +      hba-hpcp:
> > +        type: boolean
> > +        description:
> > +          Hot Plug Capable Port. Indicates that this port’s signal and power
> > +          connectors are externally accessible via a joint signal and power
> > +          connector for blindmate device hot plug. It is mutually exclusive
> > +          with the ESP feature.
> > +
> > +      hba-mpsp:
> > +        type: boolean
> > +        description:
> > +          Mechanical Presence Switch Attached to Port. Indicates whether
> > +          the platform an mechanical presence switch attached to this
> > +          port.
> > +
> > +      hba-cpd:
> > +        type: boolean
> > +        description:
> > +          Cold Presence Detection. Indicates whether the platform supports
> > +          cold presence detection on this port.
> > +
> > +      hba-esp:
> > +        type: boolean
> > +        description:
> > +          External SATA Port. Indicates that this port’s signal connector
> > +          is externally accessible on a signal only connector (e.g. eSATA
> > +          connector).
> > +
> > +      hba-fbscp:
> > +        type: boolean
> > +        description:
> > +          FIS-based Switching Capable Port. Indicates whether this port
> > +          supports Port Multiplier FIS-based switching.
> > +
> >        phys:
> >          description: Individual AHCI SATA port PHY
> >          maxItems: 1
> > @@ -111,6 +158,25 @@ patternProperties:
> >      required:
> >        - reg
> >  
> > +    # eSATA can't be enabled together with the HotPlug capability
> > +    oneOf:
> > +      - required:
> > +          - hba-hpcp
> > +      - required:
> > +          - hba-esp
> > +      - not:
> > +          anyOf:
> > +            - required:
> > +                - hba-hpcp
> > +            - required:
> > +                - hba-esp
> > +
> > +    # HotPlug capability must be enabled together with Cold Plug
> > +    # Detection and Mechanical Presence Switching.
> > +    dependencies:
> > +      hba-cpd: ["hba-hpcp"]
> > +      hba-mpsp: ["hba-hpcp"]
> > +
> >      additionalProperties: true
> >  
> >  required:
> > diff --git a/Documentation/devicetree/bindings/ata/ahci-platform.yaml b/Documentation/devicetree/bindings/ata/ahci-platform.yaml
> > index 76075d3c8987..6cad7e86f3bb 100644
> > --- a/Documentation/devicetree/bindings/ata/ahci-platform.yaml
> > +++ b/Documentation/devicetree/bindings/ata/ahci-platform.yaml
> > @@ -117,14 +117,25 @@ examples:
> >          #address-cells = <1>;
> >          #size-cells = <0>;
> >  
> > +        hba-smps;
> > +
> >          sata0: sata-port@0 {
> >              reg = <0>;
> > +
> > +            hba-fbscp;
> > +            hba-esp;
> > +
> >              phys = <&sata_phy 0>;
> >              target-supply = <&reg_sata0>;
> >          };
> >  
> >          sata1: sata-port@1 {
> >              reg = <1>;
> > +
> > +            hba-fbscp;
> > +            hba-hpcp;
> > +            hba-mpsp;
> > +
> >              phys = <&sata_phy 1>;
> >              target-supply = <&reg_sata1>;
> >          };
> > -- 
> > 2.35.1
> > 
> > 

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