Re: [PATCH 6/6] usb/ohci: Implement resume on connection status change

[Peter Maydell]

On Tue, 31 Jan 2023 at 19:39, BALATON Zoltan <balaton@eik.bme.hu> wrote:
>
> If certain bit is set remote wake up should change state from
> suspended to resume and generate interrupt. There was a todo comment
> for this, implement that by moving existing resume logic to a function
> and call that.
>
> Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
> ---
>  hw/usb/hcd-ohci.c | 23 +++++++++++++++++------
>  1 file changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
> index c5bec4e4d7..7f98ab8924 100644
> --- a/hw/usb/hcd-ohci.c
> +++ b/hw/usb/hcd-ohci.c
> @@ -1401,6 +1401,18 @@ static void ohci_set_hub_status(OHCIState *ohci, 
> uint32_t val)
>      }
>  }
>
> +/* This is the one state transition the controller can do by itself */
> +static int ohci_resume(OHCIState *s)
> +{
> +    if ((s->ctl & OHCI_CTL_HCFS) == OHCI_USB_SUSPEND) {
> +        trace_usb_ohci_remote_wakeup(s->name);
> +        s->ctl &= ~OHCI_CTL_HCFS;
> +        s->ctl |= OHCI_USB_RESUME;
> +        return 1;
> +    }
> +    return 0;
> +}
> +
>  /*
>   * Sets a flag in a port status reg but only set it if the port is connected.
>   * If not set ConnectStatusChange flag. If flag is enabled return 1.
> @@ -1417,7 +1429,10 @@ static int ohci_port_set_if_connected(OHCIState *ohci, 
> int i, uint32_t val)
>      if (!(ohci->rhport[i].ctrl & OHCI_PORT_CCS)) {
>          ohci->rhport[i].ctrl |= OHCI_PORT_CSC;
>          if (ohci->rhstatus & OHCI_RHS_DRWE) {
> -            /* TODO: CSC is a wakeup event */
> +            /* CSC is a wakeup event */
> +            if (ohci_resume(ohci)) {
> +                ohci_set_interrupt(ohci, OHCI_INTR_RD);
> +            }
>          }
>          return 0;
>      }
> @@ -1820,11 +1835,7 @@ static void ohci_wakeup(USBPort *port1)
>          intr = OHCI_INTR_RHSC;
>      }
>      /* Note that the controller can be suspended even if this port is not */
> -    if ((s->ctl & OHCI_CTL_HCFS) == OHCI_USB_SUSPEND) {
> -        trace_usb_ohci_remote_wakeup(s->name);
> -        /* This is the one state transition the controller can do by itself 
> */

I think we should retain this comment in the factored-out function.

> -        s->ctl &= ~OHCI_CTL_HCFS;
> -        s->ctl |= OHCI_USB_RESUME;
> +    if (ohci_resume(s)) {
>          /*
>           * In suspend mode only ResumeDetected is possible, not RHSC:
>           * see the OHCI spec 5.1.2.3.

Otherwise I'll leave this one for Gerd to review since it's
USB spec stuff.

thanks
-- PMM