[v4,20/23] dt-bindings: ata: ahci: Add Baikal-T1 AHCI SATA controller DT schema

Baikal-T1 AHCI controller is based on the DWC AHCI SATA IP-core v4.10a
with the next specific settings: two SATA ports, cascaded CSR access based
on two clock domains (APB and AXI), selectable source of the reference
clock (though stable work is currently available from the external source
only), two reset lanes for the application and SATA ports domains. Other
than that the device is fully compatible with the generic DWC AHCI SATA
bindings.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Hannes Reinecke <hare@suse.de>

---

Changelog v2:
- Rename 'syscon' property to 'baikal,bt1-syscon'.
- Drop macro usage from the example node.

Changelog v4:
- Use the DWC AHCI port properties definition from the DWC AHCI SATA
  common schema. (@Rob)
- Drop Baikal-T1 syscon reference and implement the clock signal
  source in the framework of the clock controller. (@Rob)
---
 .../bindings/ata/baikal,bt1-ahci.yaml         | 116 ++++++++++++++++++
 1 file changed, 116 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/ata/baikal,bt1-ahci.yaml

On Tue, Jun 14, 2022 at 04:29:22PM -0600, Rob Herring wrote:
> On Fri, Jun 10, 2022 at 11:17:58AM +0300, Serge Semin wrote:
> > Baikal-T1 AHCI controller is based on the DWC AHCI SATA IP-core v4.10a
> > with the next specific settings: two SATA ports, cascaded CSR access based
> > on two clock domains (APB and AXI), selectable source of the reference
> > clock (though stable work is currently available from the external source
> > only), two reset lanes for the application and SATA ports domains. Other
> > than that the device is fully compatible with the generic DWC AHCI SATA
> > bindings.
> > 
> > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> > Reviewed-by: Hannes Reinecke <hare@suse.de>
> > 
> > ---
> > 
> > Changelog v2:
> > - Rename 'syscon' property to 'baikal,bt1-syscon'.
> > - Drop macro usage from the example node.
> > 
> > Changelog v4:
> > - Use the DWC AHCI port properties definition from the DWC AHCI SATA
> >   common schema. (@Rob)
> > - Drop Baikal-T1 syscon reference and implement the clock signal
> >   source in the framework of the clock controller. (@Rob)
> > ---
> >  .../bindings/ata/baikal,bt1-ahci.yaml         | 116 ++++++++++++++++++
> >  1 file changed, 116 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/ata/baikal,bt1-ahci.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/ata/baikal,bt1-ahci.yaml b/Documentation/devicetree/bindings/ata/baikal,bt1-ahci.yaml
> > new file mode 100644
> > index 000000000000..d5fbd7d561d8
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/ata/baikal,bt1-ahci.yaml
> > @@ -0,0 +1,116 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/ata/baikal,bt1-ahci.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Baikal-T1 SoC AHCI SATA controller
> > +
> > +maintainers:
> > +  - Serge Semin <fancer.lancer@gmail.com>
> > +
> > +description: |
> > +  AHCI SATA controller embedded into the Baikal-T1 SoC is based on the
> > +  DWC AHCI SATA v4.10a IP-core.
> > +
> > +allOf:
> > +  - $ref: snps,dwc-ahci.yaml#
> > +
> > +properties:
> > +  compatible:
> > +    contains:
> > +      const: baikal,bt1-ahci
> > +
> > +  clocks:
> > +    items:
> > +      - description: Peripheral APB bus clock source
> > +      - description: Application AXI BIU clock
> > +      - description: SATA Ports reference clock
> > +
> > +  clock-names:
> > +    items:
> > +      - const: pclk
> > +      - const: aclk
> > +      - const: ref
> > +
> > +  resets:
> > +    items:
> > +      - description: Application AXI BIU domain reset
> > +      - description: SATA Ports clock domain reset
> > +
> > +  reset-names:
> > +    items:
> > +      - const: arst
> > +      - const: ref
> > +
> > +  ports-implemented:
> > +    maximum: 0x3
> > +
> > +patternProperties:
> > +  "^sata-port@[0-9a-e]$":
> > +    $ref: /schemas/ata/snps,dwc-ahci.yaml#/$defs/dwc-ahci-port
> > +
> > +    properties:
> > +      reg:
> > +        minimum: 0
> > +        maximum: 1
> > +
> > +      snps,tx-ts-max:
> > +        $ref: /schemas/types.yaml#/definitions/uint32
> > +        description:
> > +          Due to having AXI3 bus interface utilized the maximum Tx DMA
> > +          transaction size can't exceed 16 beats (AxLEN[3:0]).
> > +        enum: [ 1, 2, 4, 8, 16 ]
> > +
> > +      snps,rx-ts-max:
> > +        $ref: /schemas/types.yaml#/definitions/uint32
> > +        description:
> > +          Due to having AXI3 bus interface utilized the maximum Rx DMA
> > +          transaction size can't exceed 16 beats (AxLEN[3:0]).
> > +        enum: [ 1, 2, 4, 8, 16 ]
> > +
> > +    unevaluatedProperties: false
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - interrupts
> > +  - clocks
> > +  - clock-names
> > +  - resets
> > +
> > +unevaluatedProperties: false
> > +
> > +examples:
> > +  - |
> > +    sata@1f050000 {
> > +      compatible = "baikal,bt1-ahci", "snps,dwc-ahci";
> 

> Just drop 'snps,dwc-ahci'. The generic IP block fallbacks have proven to 
> be useless.

Please see my answer to your comment to the patch
[PATCH v4 17/23] dt-bindings: ata: ahci: Add DWC AHCI SATA controller DT schema
in this series here:
https://lore.kernel.org/linux-ide/20220617193744.av27axznbogademt@mobilestation/
Let's settle the fallback usage in general otherwise I'll keep
submitting patches with such functionality and will always be getting
your notes in that regard.)

-Sergey


> 
> > +      reg = <0x1f050000 0x2000>;
> > +      #address-cells = <1>;
> > +      #size-cells = <0>;
> > +
> > +      interrupts = <0 64 4>;
> > +
> > +      clocks = <&ccu_sys 1>, <&ccu_axi 2>, <&sata_ref_clk>;
> > +      clock-names = "pclk", "aclk", "ref";
> > +
> > +      resets = <&ccu_axi 2>, <&ccu_sys 0>;
> > +      reset-names = "arst", "ref";
> > +
> > +      ports-implemented = <0x3>;
> > +
> > +      sata-port@0 {
> > +        reg = <0>;
> > +
> > +        snps,tx-ts-max = <4>;
> > +        snps,rx-ts-max = <4>;
> > +      };
> > +
> > +      sata-port@1 {
> > +        reg = <1>;
> > +
> > +        snps,tx-ts-max = <4>;
> > +        snps,rx-ts-max = <4>;
> > +      };
> > +    };
> > +...
> > -- 
> > 2.35.1
> > 
> >