Re: Re: [PATCH v2 1/3] dt-bindings: ata: eswin: Document for EIC7700 SoC ahci

[luyulin@eswincomputing.com]

Hello, Rob

Thank you very much for your reply.
I have a question that I would like to seek your advice on and clarify.

> 
> On Tue, Aug 19, 2025 at 8:54 AM Yulin Lu <luyulin@eswincomputing.com> wrote:
> >
> > From: luyulin <luyulin@eswincomputing.com>
> 
> Please fix your name.
> 
> >
> > Add document for the SATA AHCI controller on the EIC7700 SoC platform,
> > including descriptions of its hardware configurations.
> >
> > Signed-off-by: luyulin <luyulin@eswincomputing.com>
> 
> And here.
> 
> > ---
> >  .../bindings/ata/eswin,eic7700-ahci.yaml      | 92 +++++++++++++++++++
> >  1 file changed, 92 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/ata/eswin,eic7700-ahci.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/ata/eswin,eic7700-ahci.yaml b/Documentation/devicetree/bindings/ata/eswin,eic7700-ahci.yaml
> > new file mode 100644
> > index 000000000000..9ef58c9c2f28
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/ata/eswin,eic7700-ahci.yaml
> > @@ -0,0 +1,92 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/ata/eswin,eic7700-ahci.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Eswin EIC7700 SoC SATA Controller
> > +
> > +maintainers:
> > +  - Yulin Lu <luyulin@eswincomputing.com>
> > +  - Huan He <hehuan1@eswincomputing.com>
> > +
> > +description:
> > +  This document defines device tree bindings for the Synopsys DWC
> > +  implementation of the AHCI SATA controller found in Eswin's
> > +  Eic7700 SoC platform.
> > +
> > +select:
> > +  properties:
> > +    compatible:
> > +      const: eswin,eic7700-ahci
> > +  required:
> > +    - compatible
> > +
> > +allOf:
> > +  - $ref: snps,dwc-ahci-common.yaml#
> > +
> > +properties:
> > +  compatible:
> > +    items:
> > +      - const: eswin,eic7700-ahci
> > +      - const: snps,dwc-ahci
> > +
> > +  reg:
> > +    maxItems: 1
> 
> Drop. snps,dwc-ahci-common.yaml already defines this.
> 
> > +
> > +  interrupts:
> > +    maxItems: 1
> 
> Drop. snps,dwc-ahci-common.yaml already defines this.
> 
> > +
> > +  ports-implemented:
> > +    const: 1
> 
> Really, your firmware should initialize the DWC specific register that
> sets this and is discoverable via a standard AHCI register.
> 

Accord to my understanding, if ports-implemented is configured in the dts,
this register will be set by the platform driver in libahci_platform.c.

Do you mean that ports-implemented should be removed from the dts,
and the corresponding register should be configured by the firmware
(which is U-Boot on the HiFive Premier P550 board)? Is this understanding correct?
If so, when the driver is removed, a reset will be triggered,
causing the configuration of this register to be lost,
which will result in an error when insmod the driver again.

Best regards,
Yulin