On Wed, Mar 18, 2015 at 03:55:57PM +0200, Roger Quadros wrote:
> The OTG core instantiates the OTG Finite State Machine
> per OTG controller and manages starting/stopping the
> host and gadget controllers based on the bus state.
>
> It provides APIs for the following tasks
>
> - Registering an OTG capable controller
> - Registering Host and Gadget controllers to OTG core
> - Providing inputs to and kicking the OTG state machine
>
> TODO:
> - sysfs interface to allow application inputs to OTG state machine
> - otg class?
>
> Signed-off-by: Roger Quadros <rog...@ti.com>
> ---
> +struct otg_data {
> + struct device *dev; /* HCD & GCD's parent device */
> +
> + struct otg_fsm fsm;
> + /* HCD, GCD and usb_otg_state are present in otg_fsm->otg
> + * HCD is bus_to_hcd(fsm->otg->host)
> + * GCD is fsm->otg->gadget
> + */
> + struct otg_fsm_ops fsm_ops; /* private copy for override */
> + struct usb_otg otg;
> + struct usb_hcd *shared_hcd; /* if shared HCD registered */
> +
> + /* saved hooks to OTG device */
> + int (*start_host)(struct otg_fsm *fsm, int on);
> + int (*start_gadget)(struct otg_fsm *fsm, int on);
> +
> + struct list_head list;
> +
> + struct work_struct work; /* OTG FSM work */
> + struct workqueue_struct *wq;
> +
> + struct otg_timer timers[NUM_OTG_FSM_TIMERS];
> +
> + bool fsm_running;
> + bool gadget_can_start; /* OTG FSM says gadget can start */
> + bool host_can_start; /* OTG FSM says host can start */
Do not understand above 2 *_can_start flags from the patch, which are set
only when you really start host/gadget, to prevent host/gadget driver to
start it out of otg fsm control?
Li Jun
> +
> + /* use otg->fsm.lock for serializing access */
> +};
> +
> + * Can be called in IRQ context.
> + */
> +void usb_otg_sync_inputs(struct otg_fsm *fsm)
> +{
> + struct otg_data *otgd = container_of(fsm, struct otg_data, fsm);
> +
> + /* Don't kick FSM till it has started */
> + if (!otgd->fsm_running)
> + return;
> +
> + /* Kick FSM */
> + queue_work(otgd->wq, &otgd->work);
> +}
> +EXPORT_SYMBOL_GPL(usb_otg_sync_inputs);
> +
> +/**
> + * usb_otg_kick_fsm - Kick the OTG state machine
> + * @hcd_gcd_device: Host/Gadget controller device
> + *
> + * Used by USB host/device stack to sync OTG related
> + * events to the OTG state machine.
> + * e.g. change in host_bus->b_hnp_enable, gadget->b_hnp_enable
> + *
There are quite a few otg fsm variables which should be updated when
events/interrupts(b_conn, a_srp_det, ...) occur, how is your plan to
update them? Still rely on specific controller driver irq handler to
capture all those events and update them?
Li Jun
> + * Returns: 0 on success, error value otherwise.
> + */
> +int usb_otg_kick_fsm(struct device *hcd_gcd_device)
> +{
> + struct otg_data *otgd;
> +
> + mutex_lock(&otg_list_mutex);
> + otgd = usb_otg_device_get_otgd(hcd_gcd_device->parent);
> + if (!otgd) {
> + dev_err(hcd_gcd_device, "%s: invalid host/gadget device\n",
> + __func__);
> + mutex_unlock(&otg_list_mutex);
> + return -ENODEV;
> + }
> +
> + mutex_unlock(&otg_list_mutex);
> + usb_otg_sync_inputs(&otgd->fsm);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_otg_kick_fsm);
> --
> 2.1.0
>
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