Re: [PATCH v3 12/23] dt-bindings: ata: ahci: Add platform capability properties

Serge Semin
2022-05-22T17:43:42Z

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@baikalelectronics.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
> >
> >