Generic USB EHCI Controller

USB EHCI controller

GPL-2.0으로 배포되는 이 schema는 USB EHCI controller를 정의합니다. 관리자는 Greg Kroah-Hartman입니다.

공통 HCD와 IBM register 예외

공통 host controller 정의는 `usb-hcd.yaml`을 상속합니다. `compatible`에 `ibm,usb-ehci-440epx`가 포함되지 않은 controller는 register 영역을 최대 하나만 허용합니다. 해당 IBM controller만 두 영역을 사용할 수 있습니다.

allOf:
  - $ref: usb-hcd.yaml
  - if:
      properties:
        compatible:
          not:
            contains:
              const: ibm,usb-ehci-440epx
    then:
      properties:
        reg:
          maxItems: 1

Platform별 EHCI compatible과 fallback

`generic-ehci` fallback을 쓰는 첫 그룹에는 Allwinner Sun4i·Sun5i·Sun6i·Sun7i·Sun8i·Sun9i·Sun20i·Sun50i·Sun55i 계열, Aspeed AST2400·2500·2600, Broadcom BCM3384·63268·6328·6358·6362·6368·7125·7346·7358·7360·7362·7420·7425·7435가 포함됩니다.

같은 그룹에는 HPE GXP, IBM 476GTR, NXP LPC1850, QCA AR7100, Rockchip RK3588, Synopsys HSDK v1.0, Socionext UniPhier도 포함됩니다.

`usb-ehci` fallback 그룹은 Atmel AT91SAM9G45, Cavium Octeon 6335, IBM 440EPX·460EX, Nintendo Hollywood, ST SPEAr600입니다.

standalone 값으로 `generic-ehci`, Marvell AC5·Armada 3700·Orion, Nuvoton NPCM750·NPCM845, TI OMAP EHCI, `usb-ehci`, VIA VT8500을 허용합니다. 정확한 SoC 문자열과 순서는 아래 원문 block에 보존됩니다.

properties:
  compatible:
    oneOf:
      - items:
          - enum:
              - allwinner,sun4i-a10-ehci
              - allwinner,sun50i-a100-ehci
              - allwinner,sun50i-a64-ehci
              - allwinner,sun50i-h6-ehci
              - allwinner,sun50i-h616-ehci
              - allwinner,sun55i-a523-ehci
              - allwinner,sun5i-a13-ehci
              - allwinner,sun6i-a31-ehci
              - allwinner,sun7i-a20-ehci
              - allwinner,sun8i-a23-ehci
              - allwinner,sun8i-a83t-ehci
              - allwinner,sun8i-h3-ehci
              - allwinner,sun8i-r40-ehci
              - allwinner,sun8i-v3s-ehci
              - allwinner,sun9i-a80-ehci
              - allwinner,sun20i-d1-ehci
              - aspeed,ast2400-ehci
              - aspeed,ast2500-ehci
              - aspeed,ast2600-ehci
              - brcm,bcm3384-ehci
              - brcm,bcm63268-ehci
              - brcm,bcm6328-ehci
              - brcm,bcm6358-ehci
              - brcm,bcm6362-ehci
              - brcm,bcm6368-ehci
              - brcm,bcm7125-ehci
              - brcm,bcm7346-ehci
              - brcm,bcm7358-ehci
              - brcm,bcm7360-ehci
              - brcm,bcm7362-ehci
              - brcm,bcm7420-ehci
              - brcm,bcm7425-ehci
              - brcm,bcm7435-ehci
              - hpe,gxp-ehci
              - ibm,476gtr-ehci
              - nxp,lpc1850-ehci
              - qca,ar7100-ehci
              - rockchip,rk3588-ehci
              - snps,hsdk-v1.0-ehci
              - socionext,uniphier-ehci
          - const: generic-ehci
      - items:
          - enum:
              - atmel,at91sam9g45-ehci
              - cavium,octeon-6335-ehci
              - ibm,usb-ehci-440epx
              - ibm,usb-ehci-460ex
              - nintendo,hollywood-usb-ehci
              - st,spear600-ehci
          - const: usb-ehci
      - enum:
          - generic-ehci
          - marvell,ac5-ehci
          - marvell,armada-3700-ehci
          - marvell,orion-ehci
          - nuvoton,npcm750-ehci
          - nuvoton,npcm845-ehci
          - ti,ehci-omap
          - usb-ehci
          - via,vt8500-ehci

Register, reset, clock과 power domain

register 영역은 1~2개지만 앞선 조건에 따라 일반 controller는 최대 하나입니다. interrupt는 최대 하나, reset과 clock은 각각 1~4개, power domain은 최대 하나입니다.

Renesas R-Car Gen3에서 host-only channel의 첫 clock은 host clock입니다. USB DRD channel은 첫 clock이 host, 둘째 clock이 peripheral이어야 합니다.

reg:
  minItems: 1
  maxItems: 2

interrupts:
  maxItems: 1

resets:
  minItems: 1
  maxItems: 4

clocks:
  minItems: 1
  maxItems: 4
  description: |
    In case the Renesas R-Car Gen3 SoCs:
      - if a host only channel: first clock should be host.
      - if a USB DRD channel: first clock should be host and second
        one should be peripheral

power-domains:
  maxItems: 1

Endian, transaction translator와 PHY

`big-endian`은 descriptor와 register가 모두 big-endian일 때, `big-endian-desc`는 descriptor만, `big-endian-regs`는 register만 big-endian일 때 설정합니다.

`has-transaction-translator`는 EHCI root hub에 Transaction Translator가 내장됐음을 뜻합니다. `needs-reset-on-resume`은 resume 뒤 EHCI reset을 강제합니다. `spurious-oc`는 실제 과전류가 없는데 hardware가 간헐적으로 OC bit를 켜는 경우를 표시합니다.

PHY는 1~3개이고 이름은 `usb`입니다. IOMMU는 최대 하나이며 `dr_mode`는 `host` 또는 `otg`입니다.

big-endian:
  $ref: /schemas/types.yaml#/definitions/flag
  description:
    Set this flag for HCDs with big endian descriptors and big
    endian registers.

big-endian-desc:
  $ref: /schemas/types.yaml#/definitions/flag
  description:
    Set this flag for HCDs with big endian descriptors.

big-endian-regs:
  $ref: /schemas/types.yaml#/definitions/flag
  description:
    Set this flag for HCDs with big endian registers.

has-transaction-translator:
  $ref: /schemas/types.yaml#/definitions/flag
  description:
    Set this flag if EHCI has a Transaction Translator built into
    the root hub.

needs-reset-on-resume:
  $ref: /schemas/types.yaml#/definitions/flag
  description:
    Set this flag to force EHCI reset after resume.

spurious-oc:
  $ref: /schemas/types.yaml#/definitions/flag
  description:
    Set this flag to indicate that the hardware sometimes turns on
    the OC bit when an over-current isn't actually present.

phys:
  minItems: 1
  maxItems: 3

phy-names:
  const: usb

iommus:
  maxItems: 1

dr_mode:
  enum:
    - host
    - otg

필수 속성과 추가 속성 제한

필수 속성은 `compatible`, `reg`, `interrupts`입니다. 상속 schema까지 평가한 뒤 남는 추가 속성은 허용하지 않습니다.

required:
  - compatible
  - reg
  - interrupts

unevaluatedProperties: false

IBM 440EPX와 Allwinner 예제

첫 예제는 IBM 440EPX의 두 register 영역, UIC0 interrupt와 `big-endian` flag를 보여 줍니다.

둘째 예제는 Allwinner Sun4i A10과 `generic-ehci` fallback, 0x100-byte register 영역, interrupt 39, AHB gate clock, USB PHY와 `usb` PHY 이름을 사용합니다.

examples:
  - |
    usb@e0000300 {
        compatible = "ibm,usb-ehci-440epx", "usb-ehci";
        interrupt-parent = <&UIC0>;
        interrupts = <0x1a 4>;
        reg = <0xe0000300 90>, <0xe0000390 70>;
        big-endian;
    };

  - |
    ehci0: usb@1c14000 {
        compatible = "allwinner,sun4i-a10-ehci", "generic-ehci";
        reg = <0x01c14000 0x100>;
        interrupts = <39>;
        clocks = <&ahb_gates 1>;
        phys = <&usbphy 1>;
        phy-names = "usb";
    };

...