On Thu, 18 Jul 2013, Felipe Balbi wrote:
> > > yes. Only the UDC driver knows when the controller is moving among those
> > > states.
> >
> > Not quite. Only the gadget driver knows when the transition between
> > ADDRESS and CONFIGURED occurs. This should be added to composite.c.
>
> that's not entirely true :-) See how we handle that in dwc3:
>
> | static int dwc3_ep0_set_config(struct dwc3 *dwc, struct usb_ctrlrequest
> *ctrl)
> | {
> | enum usb_device_state state = dwc->gadget.state;
> | u32 cfg;
> | int ret;
> | u32 reg;
> |
> | dwc->start_config_issued = false;
> | cfg = le16_to_cpu(ctrl->wValue);
> |
> | switch (state) {
> | case USB_STATE_DEFAULT:
> | return -EINVAL;
> | break;
> |
> | case USB_STATE_ADDRESS:
> | ret = dwc3_ep0_delegate_req(dwc, ctrl);
> | /* if the cfg matches and the cfg is non zero */
> | if (cfg && (!ret || (ret == USB_GADGET_DELAYED_STATUS))) {
> | usb_gadget_set_state(&dwc->gadget,
> | USB_STATE_CONFIGURED);
In theory, this should not occur until the gadget driver has finished
the transition to the CONFIGURED state, which doesn't occur until later
in the case of USB_GADGET_DELAYED_STATUS.
> |
> | /*
> | * Enable transition to U1/U2 state when
> | * nothing is pending from application.
> | */
> | reg = dwc3_readl(dwc->regs, DWC3_DCTL);
> | reg |= (DWC3_DCTL_ACCEPTU1ENA | DWC3_DCTL_ACCEPTU2ENA);
> | dwc3_writel(dwc->regs, DWC3_DCTL, reg);
> |
> | dwc->resize_fifos = true;
> | dev_dbg(dwc->dev, "resize fifos flag SET\n");
> | }
> | break;
> |
> | case USB_STATE_CONFIGURED:
> | ret = dwc3_ep0_delegate_req(dwc, ctrl);
> | if (!cfg)
> | usb_gadget_set_state(&dwc->gadget,
> | USB_STATE_ADDRESS);
No check on the value of ret? What if the request was rejected?
> | break;
> | default:
> | ret = -EINVAL;
> | }
> | return ret;
> | }
This illustrates the folly of exposing your code to public review. :-)
Nevertheless, I take your point.
> Also, until other gadget drivers add notifications to the other cases, I
> don't think it's wise to add a transition from NOTATTACHED to
> CONFIGURED.
Another good point.
Alan Stern
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