ehci: update config to improve performance

[chenzhihong007]

• update config to improve performance

Summary by CodeRabbit

• Refactor
  • Enhanced the USB host controller's initialization process. The update preserves current hardware settings and fine-tunes configuration parameters to improve overall stability and adaptability across different system environments.

[coderabbitai]

Walkthrough

The pull request updates the usb_hc_init function in the USB host controller module. Instead of initializing the regval variable to zero, it now reads the current register value from EHCI_HCOR->usbcmd. Specific bits corresponding to the interrupt threshold and frame list size are cleared using bitwise operations. Furthermore, a conditionally applied setting for the interrupt threshold is introduced based on the CONFIG_USB_EHCI_HPMICRO definition, ensuring the register configuration accounts for diverse hardware settings.

Changes

File(s)	Change Summary
port/.../usb_hc_ehci.c	In usb_hc_init, regval is now set to the current command register value instead of zero. Cleared specific bits using masks and conditionally set EHCI_USBCMD_ITHRE_1MF if CONFIG_USB_EHCI_HPMICRO is defined.

Sequence Diagram(s)

sequenceDiagram
    participant INIT as usb_hc_init
    participant REG as EHCI_HCOR
    INIT->>REG: Read current usbcmd value
    INIT->>INIT: Clear EHCI_USBCMD_ITHRE_MASK & EHCI_USBCMD_FLSIZE_MASK bits
    alt CONFIG_USB_EHCI_HPMICRO defined
        INIT->>INIT: Set EHCI_USBCMD_ITHRE_1MF bit conditionally
    end
    INIT->>REG: Write updated regval back

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📥 Commits

Reviewing files that changed from the base of the PR and between 4c64bc7 and c7c8ae3.

📒 Files selected for processing (1)

• port/ehci/usb_hc_ehci.c (2 hunks)

🚧 Files skipped from review as they are similar to previous changes (1)

• port/ehci/usb_hc_ehci.c

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